JP2003268559A - Electroless gold plating solution and electroless gold plating method - Google Patents
Electroless gold plating solution and electroless gold plating methodInfo
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- JP2003268559A JP2003268559A JP2002072824A JP2002072824A JP2003268559A JP 2003268559 A JP2003268559 A JP 2003268559A JP 2002072824 A JP2002072824 A JP 2002072824A JP 2002072824 A JP2002072824 A JP 2002072824A JP 2003268559 A JP2003268559 A JP 2003268559A
- Authority
- JP
- Japan
- Prior art keywords
- plating solution
- gold plating
- electroless gold
- salt
- heavy metal
- Prior art date
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、無電解金めっき液
及び無電解金めっき方法に関する。TECHNICAL FIELD The present invention relates to an electroless gold plating solution and an electroless gold plating method.
【０００２】[0002]
【従来の技術】従来の高温、高アルカリ性無電解金めっ
き液に代わって、中性及び低温で使用可能な無電解金め
っき液が近年開発されている。かかる無電解金めっき液
は、めっき可能なレジストや電子部品の使用範囲を広げ
ることを目的として開発されたものであるが、既存の製
品ではめっき液の安定性が不充分であり、付きまわり性
にも劣っている。2. Description of the Related Art In recent years, an electroless gold plating solution that can be used at neutral and low temperatures has been developed in place of the conventional high temperature, highly alkaline electroless gold plating solution. This electroless gold plating solution was developed with the purpose of expanding the range of use of resists and electronic parts that can be plated, but the stability of the plating solution is insufficient with existing products, and throwing power Is inferior to
【０００３】このような安定性低下の原因としては、
（１）無電解金めっき自体の安定性が不充分であるこ
と、及び（２）めっき処理による不純物金属混入により
安定性が低下すること、の２つが想定されており、これ
らの観点からめっき液を改良する試みがなされている。The cause of such decrease in stability is as follows.
It is assumed that (1) the electroless gold plating itself has insufficient stability, and (2) that the stability deteriorates due to the inclusion of an impurity metal during the plating treatment. Attempts have been made to improve the.
【０００４】例えば、特開平１−１９１７８２号公報に
は、シアン化合物を使用することなく、中性付近で無電
解金めっきを実現するために、還元剤としてアスコルビ
ン酸を使用することが開示されている。For example, JP-A-1-191782 discloses the use of ascorbic acid as a reducing agent in order to realize electroless gold plating in the vicinity of neutrality without using a cyanide compound. There is.
【０００５】また、めっき処理による不純物金属混入の
抑制や液安定性向上のために、メルカプトベンゾチアゾ
ール系化合物の金属隠蔽剤を添加することが、特開平４
−３５０１７２号公報及び特開平６−１４５９９７号公
報に開示されている。Further, in order to suppress the inclusion of impurity metals due to the plating treatment and to improve the stability of the solution, it is known to add a metal masking agent of a mercaptobenzothiazole type compound, as disclosed in Japanese Patent Laid-Open Publication No. Hei 4 (1998).
-350172 and JP-A-6-145997.
【０００６】更に、特開平３−２１５６７７号公報に
は、無電解金めっき液に還元剤としてヒドラジン化合物
（１０〜３０ｇ／Ｌ）を使用することが開示され、この
浴は上記のアスコルビン酸浴と比較して低濃度で実用的
な析出速度が得られるとされている。Further, JP-A-3-215677 discloses that a hydrazine compound (10 to 30 g / L) is used as a reducing agent in an electroless gold plating solution, and this bath is the above ascorbic acid bath. By comparison, it is said that a practical deposition rate can be obtained at a low concentration.
【０００７】また、めっき処理による不純物金属混入の
抑制や液安定性向上のためベンゾトリアゾール系化合物
の金属隠蔽剤を添加する改良がなされており、この隠蔽
剤の管理範囲は広く（３〜１０ｇ／Ｌ）実用的であるこ
とが、特開平４−３１４８７１号公報に開示されてい
る。[0007] Further, in order to suppress the inclusion of impurity metals due to plating treatment and to improve the liquid stability, improvements have been made by adding a metal masking agent of a benzotriazole compound, and the management range of this masking agent is wide (3 to 10 g / L) Practicality is disclosed in JP-A-4-314871.
【０００８】一方、特許第２９７２２０９号公報には、
還元剤にチオ尿素またはフェニル系化合物を使用する方
法が開示されており、チオ尿素は低濃度で金を還元でき
ることが示されている。On the other hand, Japanese Patent No. 2972209 discloses that
A method of using thiourea or a phenyl compound as a reducing agent has been disclosed, and it has been shown that thiourea can reduce gold at a low concentration.
【０００９】[0009]
【発明が解決しようとする課題】しかしながら、上記従
来技術のめっき液には以下のような問題点が存在してい
た。すなわち、アスコルビン酸による還元は還元効率が
低く、実用析出速度を確保するために、アスコルビン酸
ナトリウム濃度を６０〜１００ｇ／Ｌと過剰に配合する
ため、めっき液の安定性が低下していた。However, the above-mentioned conventional plating solutions have the following problems. That is, reduction with ascorbic acid has a low reduction efficiency, and in order to secure a practical deposition rate, the concentration of sodium ascorbate is excessively mixed with 60 to 100 g / L, so that the stability of the plating solution is lowered.
【００１０】また、メルカプトベンゾチアゾール系化合
物の金属隠蔽剤は、使用管理範囲が非常に狭く（０．１
〜５ｐｐｍ）、作業の効率が低く、添加量が多くなる
と、付きまわり不良が発生するという問題があった。Further, the metal masking agent of a mercaptobenzothiazole type compound has a very narrow use control range (0.1
˜5 ppm), the work efficiency is low, and when the addition amount is large, there is a problem that sticking defects occur.
【００１１】一方、還元剤としてヒドラジン化合物を使
用すると、この浴はアスコルビン酸浴と比較して低濃度
で実用的な析出速度を得られるものの、ヒドラジン化合
物自体の安定性が低く、液の安定性が確保できないとい
う問題があった。また、めっき処理による不純物金属混
入の抑制や液安定性向上のためベンゾトリアゾール系化
合物の金属隠蔽剤を添加する改良がなされているが、上
記のように還元剤自体の安定性が低いため、結果的に安
定性向上が不十分で実用化が困難である。On the other hand, when a hydrazine compound is used as a reducing agent, this bath can obtain a practical deposition rate at a lower concentration than the ascorbic acid bath, but the stability of the hydrazine compound itself is low and the stability of the solution is low. There was a problem that could not be secured. In addition, an improvement was made by adding a metal-masking agent of a benzotriazole-based compound in order to suppress the inclusion of an impurity metal due to plating treatment and to improve the liquid stability, but the stability of the reducing agent itself is low as described above. In terms of stability, improvement in stability is insufficient and practical application is difficult.
【００１２】また、チオ尿素化合物及びフェニル化合物
の両方の還元剤を配合した無電解金めっき液は、チオ尿
素の副生成物をフェニル化合物系還元剤で還元し、液安
定性を向上せしめたものであるが、チオ尿素の副生成物
を完全に元の還元剤にもどすことが困難であり、この残
留副生成物がめっきの付きまわり不良や不安定化の原因
となり、充分な安定性を保持できない場合があった。ま
た、フェニル化合物系還元剤は、中性（ｐＨ７〜７．
５）において還元力が少ないため実用的な析出速度を得
ることができず、弱アルカリ性領域（ｐＨ９．０付近）
においては、皮膜外観が悪くめっき中に液が分解する問
題があった。Further, the electroless gold plating solution containing reducing agents for both thiourea compound and phenyl compound is one in which by-products of thiourea are reduced by a phenyl compound type reducing agent to improve solution stability. However, it is difficult to completely return the thiourea by-product to the original reducing agent, and this residual by-product causes poor adhesion of the plating and destabilization, and maintains sufficient stability. There were times when I could not. The phenyl compound-based reducing agent is neutral (pH 7 to 7.
In 5), since the reducing power is small, a practical deposition rate cannot be obtained, and a weak alkaline region (around pH 9.0)
However, there was a problem in that the appearance of the coating was poor and the solution decomposed during plating.
【００１３】そこで、チオ尿素化合物、フェニル化合物
の両方の還元剤を配合した無電解金めっき液が提案され
ており（特開平３−１０４８７７号公報）、このめっき
液によれば、チオ尿素の副生成物がフェニル化合物系還
元剤で還元されるため、液安定性が向上することが可能
になる。また、この浴にベンゾトリアゾール系化合物の
金属隠蔽剤を添加することが提案されており（特開平９
−１５７８５９号公報）、このめっき液によれば、不純
物金属混入の抑制や液安定性向上を図り、従来浴に比べ
て安定性を向上させることが可能になる。Therefore, an electroless gold plating solution containing a reducing agent for both a thiourea compound and a phenyl compound has been proposed (JP-A-3-104877). Since the product is reduced with the phenyl compound-based reducing agent, the liquid stability can be improved. In addition, it has been proposed to add a metal masking agent of a benzotriazole-based compound to this bath (Japanese Patent Laid-Open Publication No. H9-96952).
According to this plating solution, it is possible to suppress the mixing of impurity metals and improve the solution stability, and to improve the stability as compared with the conventional bath.
【００１４】しかしながら、安定性が更に高く、中性且
つ低温で実用的な析出速度を発揮するめっき液が求めら
れているのが現状である。そこで、本発明の目的は、ｐ
Ｈ６〜８程度の中性領域において液温６０〜８０℃程度
の低温でも、充分な金の析出速度を発揮する無電解金め
っき液であって、めっき液の安定性が特に優れた無電解
金めっき液を提供することにある。本発明の目的は、ま
た、かかる無電解金めっき液を用いた無電解金めっき方
法を提供することにある。However, under the present circumstances, there is a demand for a plating solution having higher stability, neutrality, and a practical deposition rate at a low temperature. Therefore, the object of the present invention is to
It is an electroless gold plating solution that exhibits a sufficient gold deposition rate even in a low temperature of about 60 to 80 ° C. in a neutral region of H6 to 8, and the stability of the plating solution is particularly excellent. To provide a plating solution. Another object of the present invention is to provide an electroless gold plating method using such an electroless gold plating solution.
【００１５】[0015]
【課題を解決するための手段】本発明者らは、上記目的
を達成すべく鋭意研究を重ねた結果、特定の還元剤と重
金属塩を含む無電解金めっき液により、上記目的が達成
可能であることを見出し、本発明を完成させた。As a result of intensive studies to achieve the above object, the present inventors have found that the above object can be achieved by an electroless gold plating solution containing a specific reducing agent and a heavy metal salt. The inventors have found that there is and have completed the present invention.
【００１６】すなわち、本発明の無電解金めっき液は、
金塩と、下記一般式（Ｉ）で表される還元剤と、重金属
塩と、を含むことを特徴とするものである。That is, the electroless gold plating solution of the present invention is
It is characterized by containing a gold salt, a reducing agent represented by the following general formula (I), and a heavy metal salt.
【００１７】[0017]
【化３】
［式中、Ｒ1は水酸基又はアミノ基を示し、Ｒ2、Ｒ3及
びＲ4はそれぞれ独立に水酸基、アミノ基、水素原子又
はアルキル基を示す。］[Chemical 3] [In the formula, R 1 represents a hydroxyl group or an amino group, and R 2 , R 3 and R 4 each independently represent a hydroxyl group, an amino group, a hydrogen atom or an alkyl group. ]
【００１８】本発明の無電解金めっき液は、金塩と組み
合わせる還元剤を上記一般式（Ｉ）で表される化合物と
し、重金属塩を併用したことから、ｐＨ６〜８程度の中
性領域において液温６０〜８０℃程度の低温でも、充分
な金の析出速度を発揮するのみならず、めっき液の安定
性が特に優れるようになる。In the electroless gold plating solution of the present invention, the reducing agent to be combined with the gold salt is the compound represented by the general formula (I), and the heavy metal salt is used in combination. Even when the liquid temperature is as low as about 60 to 80 ° C., not only a sufficient gold deposition rate is exhibited, but also the stability of the plating liquid becomes particularly excellent.
【００１９】上記本発明の無電解金めっき液は、錯化剤
を更に含むことが好ましく、ｐＨ緩衝剤を更に含むこと
が好ましく、金属イオン隠蔽剤を更に含むことが好まし
い。すなわち、本発明の無電解金めっき液は、錯化剤、
ｐＨ緩衝剤及び金属イオン隠蔽剤のうち少なくとも１つ
を更に含むことが好ましい。かかる成分を含有すること
により、めっき液の安定性が更に優れるようになる。The electroless gold plating solution of the present invention preferably further contains a complexing agent, preferably a pH buffering agent, and further preferably a metal ion concealing agent. That is, the electroless gold plating solution of the present invention is a complexing agent,
It is preferable to further include at least one of a pH buffering agent and a metal ion masking agent. By containing such components, the stability of the plating solution will be further improved.
【００２０】そして、重金属塩は、タリウム塩、鉛塩、
砒素塩、アンチモン塩、テルル塩及びビスマス塩からな
る群より選ばれる少なくとも１つの重金属塩であること
が好ましく、重金属塩はタリウム塩であることが特に好
ましい。また、重金属塩としては重金属無機化合物塩又
は重金属有機錯体塩が良く、無電解金めっき液は、重金
属塩に由来する重金属が１〜１００ｐｐｍとなるように
重金属塩を含有することが好適である。重金属塩が上記
化合物である場合又は上記濃度である場合には、金の析
出速度及びめっき液の安定性が更に優れるようになる。Heavy metal salts include thallium salts, lead salts,
At least one heavy metal salt selected from the group consisting of arsenic salts, antimony salts, tellurium salts and bismuth salts is preferable, and the heavy metal salt is particularly preferably thallium salt. The heavy metal salt is preferably a heavy metal inorganic compound salt or a heavy metal organic complex salt, and the electroless gold plating solution preferably contains the heavy metal salt so that the heavy metal derived from the heavy metal salt is 1 to 100 ppm. When the heavy metal salt is the above compound or has the above concentration, the deposition rate of gold and the stability of the plating solution are further improved.
【００２１】本発明の無電解金めっき液においては、還
元剤が、下記一般式（II）で表される還元剤であること
が好ましい。一般式（II）で表される還元剤を用いるこ
とによりめっき液の安定性が高まると共に、金の析出速
度を向上させることが可能になる。In the electroless gold plating solution of the present invention, the reducing agent is preferably a reducing agent represented by the following general formula (II). By using the reducing agent represented by the general formula (II), the stability of the plating solution can be increased and the gold deposition rate can be improved.
【００２２】[0022]
【化４】
［式中、Ｒ21は水酸基又はアミノ基を示し、Ｒ22は水素
原子又は炭素数１〜４のアルキル基を示す。］[Chemical 4] [In the formula, R 21 represents a hydroxyl group or an amino group, and R 22 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ]
【００２３】本発明の無電解金めっき液は、ｐＨが５〜
１０であることが好ましい。無電解金めっき液のｐHが
上記範囲である場合は、様々な被めっき体に対して中性
且つ低温で無電解金めっきが可能なることから、めっき
可能なレジストや電子部品の使用範囲を広げることが可
能になる。The electroless gold plating solution of the present invention has a pH of 5 to 5.
It is preferably 10. When the pH of the electroless gold plating solution is in the above range, it is possible to perform electroless gold plating on various objects to be plated at neutral and low temperature, thus expanding the range of use of resists and electronic parts that can be plated. It will be possible.
【００２４】本発明は、また、ｐＨ６〜８、液温６０〜
８０℃における金の析出速度が０．２〜１．０μｍ／時
であり、０．３６ｄｍ2／Ｌのめっき負荷で６５℃にお
いて１時間めっきを行った後に室温で１日放置したとき
の異常析出成分が０％であることを特徴とする無電解金
めっき液を提供する。The present invention also has a pH of 6 to 8 and a liquid temperature of 60 to
The deposition rate of gold at 80 ° C. is 0.2 to 1.0 μm / hour, and abnormal deposition occurs when plating is performed for 1 hour at 65 ° C. under a plating load of 0.36 dm 2 / L and then left at room temperature for 1 day. Provided is an electroless gold plating solution characterized by containing 0% of a component.
【００２５】本発明は、更に、無電解金めっき液中に被
めっき体を浸漬して該被めっき体表面に金被膜を形成さ
せる無電解金めっき方法において、無電解金めっき液は
上記本発明の無電解金めっき液であることを特徴とする
無電解金めっき方法を提供する。かかる方法において
は、無電解金めっき液のｐＨを６〜８とすることが好ま
しく、金被膜の形成を液温６０〜８０℃の無電解めっき
液で行うことが好ましい。かかる方法を適用することに
より、様々な被めっき体に対して中性且つ低温で無電解
金めっきが可能なる。The present invention further provides an electroless gold plating method in which an object to be plated is immersed in an electroless gold plating solution to form a gold coating on the surface of the object to be plated, wherein the electroless gold plating solution is the above-mentioned invention. And an electroless gold plating method. In this method, the electroless gold plating solution preferably has a pH of 6 to 8, and the gold coating is preferably formed with an electroless plating solution having a liquid temperature of 60 to 80 ° C. By applying such a method, electroless gold plating can be performed on various objects to be plated at neutral temperature and low temperature.
【００２６】[0026]
【発明の実施の形態】本発明の無電解金めっき液は、上
述のように、必須成分として、金塩、還元剤及び重金属
塩を含有している、先ず、かかる必須成分の実施の形態
について説明する。BEST MODE FOR CARRYING OUT THE INVENTION As described above, the electroless gold plating solution of the present invention contains a gold salt, a reducing agent and a heavy metal salt as essential components. First, an embodiment of such essential components will be described. explain.
【００２７】（金塩）本発明の無電解金めっき液に使用
可能な金塩としては、シアン系金塩及び非シアン系金塩
が挙げられる。シアン系金塩としては、シアン化第一金
カリウム及びやシアン化第二金カリウムが例示でき、非
シアン系金塩としては、塩化金酸塩、亜硫酸金塩、チオ
硫酸金塩、チオリンゴ酸金塩が例示可能である。金塩は
１種のみ用いてもよく、２種以上を組み合わせて用いて
もよい。(Gold Salt) Examples of gold salts usable in the electroless gold plating solution of the present invention include cyan gold salts and non-cyan gold salts. Examples of the cyan gold salt include potassium potassium cyanide and potassium potassium cyanide, and examples of the non-cyan gold salt include chloroaurate, gold sulfite, gold thiosulfate, and gold thiomalate. A salt can be illustrated. Only one gold salt may be used, or two or more gold salts may be used in combination.
【００２８】金塩としては、亜硫酸金塩及びチオ硫酸金
塩が好ましく、その含有量としては金として１〜１０ｇ
／Ｌの範囲であることが好ましい。金の含有量が１ｇ／
Ｌ未満であると、金の析出反応が低下し、１０ｇ／Ｌを
超えると、めっき液の安定性が低下すると共に、めっき
液の持出により金消費量が多くなるため経済的に好まし
くない。含有量は、２〜５ｇ／Ｌの範囲とすることがよ
り好ましい。As the gold salt, gold sulfite and gold thiosulfate are preferable, and the content thereof is 1 to 10 g as gold.
It is preferably in the range of / L. Gold content is 1g /
When it is less than L, the gold precipitation reaction is reduced, and when it exceeds 10 g / L, the stability of the plating solution is reduced, and the gold consumption is increased by carrying out the plating solution, which is not economically preferable. The content is more preferably in the range of 2 to 5 g / L.
【００２９】（還元剤）本発明の無電解金めっき液にお
いて用いる還元剤は、下記一般式（Ｉ）で表される化合
物（以下「化合物Ｉ」という。）である。(Reducing Agent) The reducing agent used in the electroless gold plating solution of the present invention is a compound represented by the following general formula (I) (hereinafter referred to as “compound I”).
【００３０】[0030]
【化５】 [Chemical 5]
【００３１】化合物Ｉにおける、Ｒ1は水酸基又はアミ
ノ基、Ｒ2、Ｒ3及びＲ4はそれぞれ独立に水酸基、アミ
ノ基、水素原子又はアルキル基であるが、アルキル基と
しては、直鎖又は分岐状の炭素数１〜６のアルキル基が
好ましく、直鎖又は分岐状の炭素数１〜４のアルキル基
（メチル基、エチル基、ｔ−ブチル基等）がより好まし
い。In the compound I, R 1 is a hydroxyl group or an amino group, and R 2 , R 3 and R 4 are independently a hydroxyl group, an amino group, a hydrogen atom or an alkyl group, and the alkyl group is a straight chain or a branched group. C1-C6 alkyl group is preferable, and a linear or branched C1-C4 alkyl group (methyl group, ethyl group, t-butyl group, etc.) is more preferable.
【００３２】化合物Ｉの具体例としては、例えばフェノ
ール、ｏ−クレゾール、ｐ−クレゾール、ｏ−エチルフ
ェノール、ｐ−エチルフェノール、ｔ−ブチルフェノー
ル、ｏ−アミノフェノール、ｐ−アミノフェノール、ヒ
ドロキノン、カテコール、ピロガロール、メチルヒドロ
キノン、アニリン、ｏ−フェニレンジアミン、ｐ−フェ
ニレンジアミン、ｏ−トルイジン、ｐ−トルイジン、ｏ
−エチルアニリン、ｐ−エチルアニリン等が挙げられ、
これらの１種又は２種以上を用いることができる。Specific examples of the compound I include, for example, phenol, o-cresol, p-cresol, o-ethylphenol, p-ethylphenol, t-butylphenol, o-aminophenol, p-aminophenol, hydroquinone, catechol, Pyrogallol, methylhydroquinone, aniline, o-phenylenediamine, p-phenylenediamine, o-toluidine, p-toluidine, o
-Ethylaniline, p-ethylaniline and the like,
These 1 type (s) or 2 or more types can be used.
【００３３】めっき液の安定性及び金の析出速度の観点
からは、化合物Ｉは、下記一般式（II）で表される化合
物（以下「化合物II」という。）であることが好ましい。From the viewpoint of the stability of the plating solution and the gold deposition rate, the compound I is preferably a compound represented by the following general formula (II) (hereinafter referred to as "compound II").
【００３４】[0034]
【化６】 [Chemical 6]
【００３５】化合物IIにおいて、Ｒ21は水酸基又はアミ
ノ基、Ｒ22は水素原子又は炭素数１〜４のアルキル基
（メチル基、エチル基、ｔ−ブチル基等）である。化合
物IIの具体例としては、ｐ−フェニレンジアミン、メチ
ルヒドロキノン、ヒドロキノン等が挙げられる。In the compound II, R 21 is a hydroxyl group or an amino group, and R 22 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms (methyl group, ethyl group, t-butyl group, etc.). Specific examples of compound II include p-phenylenediamine, methylhydroquinone, hydroquinone and the like.
【００３６】還元剤の含有量は、めっき液の全容量を基
準として０．５〜５０ｇ／Ｌが好ましい。還元剤の含有
量が、０．５ｇ／Ｌ未満であると、実用的な析出速度を
得るのが困難になる。５０ｇ／Ｌを超えると、めっき液
の安定性を確保できなくなる傾向にある。還元剤の含有
量は、２〜１０ｇ／Ｌとすることがより好ましい。The content of the reducing agent is preferably 0.5 to 50 g / L based on the total volume of the plating solution. When the content of the reducing agent is less than 0.5 g / L, it becomes difficult to obtain a practical precipitation rate. If it exceeds 50 g / L, the stability of the plating solution tends to be difficult to be ensured. The content of the reducing agent is more preferably 2 to 10 g / L.
【００３７】（重金属塩）本発明においては、上述した
金塩と還元剤との組み合わせに重金属塩を添加したこと
が大きな特徴である。重金属塩を添加することにより、
ｐＨ６〜８程度の中性領域において液温６０〜８０℃程
度の低温でも、実用上充分な金の析出速度（０．２μｍ
／時以上）が可能になる。すなわち、重金属塩は析出速
度促進剤として機能する。また、従来技術では不可能で
あった優れためっき液安定性も得られるようになる。(Heavy Metal Salt) In the present invention, a major feature is that a heavy metal salt is added to the above-mentioned combination of the gold salt and the reducing agent. By adding heavy metal salts,
A gold deposition rate (0.2 μm) that is practically sufficient even at a low temperature of about 60 to 80 ° C. in the neutral region of pH 6 to 8
/ Hour or more) is possible. That is, the heavy metal salt functions as a deposition rate accelerator. Further, it becomes possible to obtain excellent plating solution stability, which was impossible with the conventional technology.
【００３８】析出速度を更に促進する観点からは、重金
属塩は、タリウム塩、鉛塩、砒素塩、アンチモン塩、テ
ルル塩及びビスマス塩からなる群より選ばれる少なくと
も１つであることが好ましい。From the viewpoint of further promoting the precipitation rate, the heavy metal salt is preferably at least one selected from the group consisting of thallium salt, lead salt, arsenic salt, antimony salt, tellurium salt and bismuth salt.
【００３９】タリウム塩としては、硫酸タリウム塩、塩
化タリウム塩、酸化タリウム塩、硝酸タリウム塩等の無
機化合物塩、マロン酸二タリウム塩等の有機錯体塩が挙
げられ、鉛塩としては、硫酸鉛塩、硝酸鉛塩等の無機化
合物塩、酢酸鉛等の有機錯体塩が挙げられる。Examples of the thallium salt include inorganic compound salts such as thallium sulfate salt, thallium chloride salt, thallium oxide salt and thallium nitrate salt, and organic complex salts such as dithallium malonate salt. Lead salts include lead sulfate. Examples thereof include salts, inorganic compound salts such as lead nitrate salts, and organic complex salts such as lead acetate.
【００４０】また、砒素塩としては、亜砒酸塩、砒酸
塩、三酸化砒素等の無機化合物塩や有機錯体塩が挙げら
れ、アンチモン塩としては、酒石酸アンチモニル塩等の
有機錯体塩、塩化アンチモン塩類、オキシ硫酸アンチモ
ン塩、三酸化アンチモン等の無機化合物塩類が挙げられ
る。Examples of the arsenic salt include salts of inorganic compounds such as arsenite, arsenate, and arsenic trioxide, and organic complex salts, and examples of the antimony salt include organic complex salts such as antimonyl tartrate salt, antimony chloride salts, and the like. Examples thereof include inorganic compound salts such as antimony oxysulfate salt and antimony trioxide.
【００４１】そして、テルル塩としては、亜テルル酸
塩、テルル酸塩等の無機化合物塩や有機錯体塩が挙げら
れ、ビスマス塩としては、硫酸ビスマス（III）、塩化
ビスマス（III）、硝酸ビスマス（III）等の無機化合物
塩、しゅう酸ビスマス（III）等の有機錯体塩が挙げら
れる。The tellurium salt may be an inorganic compound salt such as tellurite or tellurite, or an organic complex salt, and the bismuth salt may be bismuth (III) sulfate, bismuth (III) chloride, bismuth nitrate. Examples thereof include inorganic compound salts such as (III) and organic complex salts such as bismuth (III) oxalate.
【００４２】本発明においては、重金属化合物塩とし
て、タリウム塩（好ましくは、タリウム無機化合物塩又
はタリウム有機錯体塩）を用いることが特に好ましい。In the present invention, it is particularly preferable to use a thallium salt (preferably a thallium inorganic compound salt or a thallium organic complex salt) as the heavy metal compound salt.
【００４３】上述した重金属塩は１種又は２種以上を用
いることができるが、その添加量の合計はめっき液全容
量を基準として１〜１００ｐｐｍが好ましく、１〜１０
ｐｐｍがより好ましい。１ｐｐｍ未満では、析出速度向
上効果が充分でない場合があり、１００ｐｐｍを超す場
合はめっき液安定性が悪くなる傾向にある。The above-mentioned heavy metal salts may be used either individually or in combination of two or more. The total addition amount thereof is preferably 1 to 100 ppm, preferably 1 to 10 ppm, based on the total volume of the plating solution.
ppm is more preferred. If it is less than 1 ppm, the effect of improving the deposition rate may not be sufficient, and if it exceeds 100 ppm, the stability of the plating solution tends to deteriorate.
【００４４】本発明の無電解金めっき液は、上述した金
塩、還元剤及び重金属塩に加えて、錯化剤、ｐＨ緩衝剤
及び金属イオン隠蔽剤の少なくとも一つを含有すること
が好ましく、これらの全てを含有することがより好まし
い。以下、かかる成分について説明する。The electroless gold plating solution of the present invention preferably contains at least one of a complexing agent, a pH buffering agent and a metal ion masking agent in addition to the above-mentioned gold salt, reducing agent and heavy metal salt. It is more preferable to contain all of these. Hereinafter, such components will be described.
【００４５】（錯化剤）本発明の無電解金めっき液に
は、錯化剤を含有させることが好ましく、当該成分を含
有せしめることにより、金イオン（Ａｕ+）が安定的に
錯体化されて、Ａｕ+の不均化反応（３Ａｕ+＝Ａｕ3+＋
２Ａｕ）の発生を低下させ、液が安定に保たれるという
効果が得られる。錯化剤は、１種のみを用いてもよく２
種類以上を組み合わせて用いてもよく、好適な錯化剤と
しては、シアン系錯化剤及び／又は非シアン系錯化剤が
挙げられる。(Complexing Agent) It is preferable that the electroless gold plating solution of the present invention contains a complexing agent, and by containing the component, gold ion (Au + ) is stably complexed. The disproportionation reaction of Au + ( 3 Au + = Au 3+ +
2Au) is reduced and the liquid is kept stable. Only one complexing agent may be used 2
A combination of more than one kind may be used, and suitable complexing agents include cyan complexing agents and / or non-cyan complexing agents.
【００４６】シアン系錯化剤としては、シアン化ナトリ
ウム、シアン化カリウム等のシアン塩が挙げられ、非シ
アン系錯化剤としては亜硫酸塩、チオ硫酸塩、チオリン
ゴ酸塩が挙げられる。Examples of the cyan complexing agent include cyanates such as sodium cyanide and potassium cyanide, and examples of the non-cyan complexing agent include sulfite, thiosulfate and thiomalate.
【００４７】錯化剤としては、亜硫酸塩、チオ硫酸塩が
好ましく、錯化剤の含有量は、めっき液の全容量を基準
として１〜２００ｇ／Ｌが好ましい。錯化剤の含有量が
１ｇ／Ｌ未満であると、金錯化力が低下し安定性を低下
する傾向にある。また、２００ｇ／Ｌを超えると、めっ
き液の安定性が向上するが、液中に再結晶が発生し経済
的に負担となる。錯化剤の含有量は、２０〜５０ｇ／Ｌ
とすることがより好ましい。The complexing agent is preferably a sulfite or a thiosulfate, and the content of the complexing agent is preferably 1 to 200 g / L based on the total volume of the plating solution. If the content of the complexing agent is less than 1 g / L, the gold complexing power tends to decrease and the stability tends to decrease. On the other hand, when it exceeds 200 g / L, the stability of the plating solution is improved, but recrystallization occurs in the solution, which is an economical burden. Content of complexing agent is 20 to 50 g / L
Is more preferable.
【００４８】（ｐH緩衝剤）本発明の無電解金めっき液
には、ｐH緩衝剤を含有させることが好ましく、当該成
分を含有せしめることにより、析出速度を所望の値に調
整することができ、ｐＨ等を一定に保つこともできる。
ｐH緩衝剤は、１種のみを用いてもよく２種類以上を組
み合わせて用いてもよい。好適なｐH緩衝剤としては、
リン酸塩、酢酸塩、炭酸塩、硼酸塩、クエン酸塩、硫酸
塩等が挙げられ、これらの中では、硼酸塩及び／又は硫
酸塩が特に好ましい。(PH Buffer) It is preferable that the electroless gold plating solution of the present invention contains a pH buffer, and by containing the components, the deposition rate can be adjusted to a desired value. The pH and the like can be kept constant.
The pH buffer may be used alone or in combination of two or more kinds. Suitable pH buffers include
Phosphates, acetates, carbonates, borates, citrates, sulphates and the like can be mentioned, of which borate and / or sulphate are particularly preferred.
【００４９】錯化剤の含有量は、めっき液の全容量を基
準として１〜１００ｇ／Ｌが好ましい。錯化剤の含有量
が１ｇ／Ｌ未満であると、ｐＨの緩衝効果がなくめっき
浴の状態が変化する場合があり、１００ｇ／Ｌを超える
と、めっき液中で再結晶化が進行する傾向にある。錯化
剤の含有量は、２０〜５０ｇ／Ｌの範囲とすることがよ
り好ましい。The content of the complexing agent is preferably 1 to 100 g / L based on the total volume of the plating solution. If the content of the complexing agent is less than 1 g / L, the pH buffering effect may not be exerted and the state of the plating bath may change. If it exceeds 100 g / L, recrystallization tends to proceed in the plating solution. It is in. The content of the complexing agent is more preferably in the range of 20 to 50 g / L.
【００５０】（金属イオン隠蔽剤）本発明の無電解金め
っき液には、金属イオン隠蔽剤を含有させることが好ま
しく、当該成分を含有せしめることにより、以下の効果
が得られる。すなわち、作業中にめっき装置の錆や金属
破片等の持込み等による不純物の混入や、被めっき物の
付きまわり不足による下地金属のめっき液中への混入な
どによって、銅、ニッケル、鉄などの不純物イオンが混
入し、めっき液の異常反応が進行して、めっき液の分解
が発生した場合に、このような異常反応を抑制すること
が可能になる。(Metal Ion Concealing Agent) The electroless gold plating solution of the present invention preferably contains a metal ion concealing agent. By including the component, the following effects can be obtained. That is, impurities such as copper, nickel, iron, etc. due to mixing of impurities such as rust of the plating equipment or bringing in metal debris during the work, or mixing of the base metal into the plating solution due to insufficient coverage of the object to be plated. When the ions are mixed and the abnormal reaction of the plating solution proceeds and the decomposition of the plating solution occurs, such abnormal reaction can be suppressed.
【００５１】金属イオン隠蔽剤としては、ベンゾトリア
ゾール系化合物を用いることができ、かかる化合物とし
ては、ベンゾトリアゾールナトリウム、ベンゾトリアゾ
ールカリウム、テトラヒドロベンゾトリアゾール、メチ
ルベンゾトリアゾール、ニトロベンゾトリアゾール等が
例示できる。As the metal ion masking agent, a benzotriazole compound can be used, and examples of such a compound include benzotriazole sodium, benzotriazole potassium, tetrahydrobenzotriazole, methylbenzotriazole, nitrobenzotriazole and the like.
【００５２】金属イオン隠蔽剤の含有量は、めっき液の
全容量を基準として０．５〜１００ｇ／Ｌが好ましい。
金属イオン隠蔽剤の含有量が０．５ｇ／Ｌ未満である
と、不純物の隠蔽効果が少なく、充分な液安定性を確保
できない傾向にある。一方、１００ｇ／Ｌを超えると、
めっき液中に再結晶化が生じる場合がある。コスト及び
効果を考慮すると、金属イオン隠蔽剤の含有量は、２〜
１０ｇ／Ｌとすることがより好ましい。The content of the metal ion masking agent is preferably 0.5 to 100 g / L based on the total volume of the plating solution.
When the content of the metal ion concealing agent is less than 0.5 g / L, the effect of concealing impurities is small and sufficient liquid stability tends not to be secured. On the other hand, if it exceeds 100 g / L,
Recrystallization may occur in the plating solution. Considering cost and effect, the content of the metal ion masking agent is 2 to
More preferably, it is 10 g / L.
【００５３】（無電解金めっき液のｐＨ）本発明の無電
解金めっき液のｐＨは５〜１０であることが好ましい。
無電解金めっき液のｐＨが５未満であると、めっき液の
金錯化剤である亜硫酸塩や、チオ硫酸塩が分解し、毒性
の亜硫酸ガスが発生するおそれがある。また、ｐＨが１
０を超えると、めっき液の安定性が低下する傾向にあ
る。無電解金めっき液のｐHは、６〜８がより好まし
く、７〜８が更に好ましい。(PH of electroless gold plating solution) The pH of the electroless gold plating solution of the present invention is preferably 5-10.
If the pH of the electroless gold plating solution is less than 5, sulfite or thiosulfate, which is a gold complexing agent of the plating solution, may be decomposed and toxic sulfite gas may be generated. Also, the pH is 1
If it exceeds 0, the stability of the plating solution tends to decrease. The pH of the electroless gold plating solution is more preferably 6-8, further preferably 7-8.
【００５４】（無電解金めっき方法）次に、本発明の無
電解金めっき方法について説明する。本発明の無電解金
めっき方法は、上述した本発明の無電解金めっき液中に
被めっき体を浸漬して該被めっき体表面に金被膜を形成
させることを特徴とするものである。(Electroless Gold Plating Method) Next, the electroless gold plating method of the present invention will be described. The electroless gold plating method of the present invention is characterized by immersing an object to be plated in the above-mentioned electroless gold plating solution of the present invention to form a gold coating on the surface of the object to be plated.
【００５５】かかる方法においては、無電解金めっき液
のｐＨは５〜１０が好ましく、６〜８がより好ましく、
７〜８が更に好ましい。また、金被膜の形成を液温６０
〜８０℃の無電解めっき液で行うことが好ましく、液温
は６５℃〜８０℃とすることがより好ましい。In this method, the pH of the electroless gold plating solution is preferably 5-10, more preferably 6-8,
7-8 is more preferable. Also, the formation of the gold coating is performed at a liquid temperature of 60.
It is preferable to use an electroless plating solution at -80 ° C, and it is more preferable that the solution temperature be 65 ° C to 80 ° C.
【００５６】[0056]
【実施例】次に、実施例により本発明を具体的に説明す
るが、本発明はこれによって制限されるものではない。EXAMPLES Next, the present invention will be described in detail with reference to examples, but the present invention is not limited thereto.
【００５７】［試料の作成］めっき試験用サンプルには
3ｃｍ×3ｃｍ×0．3ｍｍの圧延銅板を使用し、表面の錆
や有機物等を除去するために、酸性脱脂であるZ-200
（ワールドメタル株式会社製、商品名）に45℃で3分間
処理した。更に、余分な界面活性剤を除去するために湯
洗（45℃、純水）を1分間実施した。その後、水洗処理
を１分間行った。更に、表面の形状を均一化するため
に、過硫酸アンモニウム溶液（120ｇ／L）に室温で3分
間浸漬処理するソフトエッチング処理を行った。その
後、水洗処理を1分間行った。次いで、表面の酸化銅を
除去するために硫酸（10％）に室温で1分間浸漬処理を
行い、その後、水洗処理を1分間行った後、置換パラジ
ウムめっきであるSA−100（日立化成工業株式会社製、
商品名）に室温で5分間浸漬処理を行った。その後、水
洗処理を1分間行った。[Preparation of sample] For the plating test sample,
Z-200 is an acid degreaser to remove surface rust and organic substances using a rolled copper plate of 3 cm x 3 cm x 0.3 mm.
(World Metal Co., Ltd., trade name) was treated at 45 ° C. for 3 minutes. Further, hot water washing (45 ° C., pure water) was carried out for 1 minute in order to remove excess surfactant. After that, a water washing treatment was performed for 1 minute. Furthermore, in order to make the surface shape uniform, a soft etching treatment was carried out by immersing in an ammonium persulfate solution (120 g / L) at room temperature for 3 minutes. After that, a water washing treatment was performed for 1 minute. Next, in order to remove the copper oxide on the surface, it is immersed in sulfuric acid (10%) at room temperature for 1 minute and then rinsed with water for 1 minute, followed by substitution palladium plating SA-100 (Hitachi Chemical Co., Ltd.). Company made,
Immersion treatment was performed for 5 minutes at room temperature. After that, a water washing treatment was performed for 1 minute.
【００５８】次に、無電解Ni−Pめっき液であるNIPS−1
00（日立化成工業株式会社製、商品名）に85℃で、25分
間浸漬処理をしてニッケル−リンのめっき皮膜を5μｍ
程度に行い、水洗処理を１分間行った後、置換金めっき
液であるHGS−500（日立化成工業株式会社製、商品名）
に85℃で、10分間浸漬処理して、0．05〜0．1μｍ程度
の膜厚の金めっき膜を形成させて水洗処理を1分間行
い、更に、以下の無電解金めっきを行って評価した。ま
た、無電解金めっき液の評価用めっき槽には、ポリプロ
ピレン製の樹脂槽を使用した。Next, NIPS-1 which is an electroless Ni-P plating solution
00 (Hitachi Chemical Co., Ltd., trade name) is immersed at 85 ° C. for 25 minutes to form a nickel-phosphorus plating film of 5 μm.
HGS-500 (manufactured by Hitachi Chemical Co., Ltd., trade name) which is a displacement gold plating solution after washing for about 1 minute and rinsing with water for 1 minute
Immersion treatment at 85 ℃ for 10 minutes to form a gold plating film with a thickness of about 0.05 to 0.1 μm, washing with water for 1 minute, and then performing the following electroless gold plating for evaluation did. A polypropylene resin bath was used as the plating bath for evaluation of the electroless gold plating solution.
【００５９】［金めっき液安定性評価方法］
（金めっき液安定性評価用実験槽の洗浄方法）金めっき
液安定性評価方法には、PP（ポリプロピレン製）樹脂製
の1Lビーカーをめっき槽として使用した。また、槽内に
付着している不純物を除去するために、実験前に槽内を
王水（1：3＝硝酸：塩酸、50％に純水で希釈）で6時間
以上、常温で洗浄した後、水洗、純水洗を順次、充分行
い、80℃で乾燥して実験に使用した。[Gold Plating Solution Stability Evaluation Method] (Cleaning Method of Gold Plating Solution Stability Evaluation Experimental Tank) As a gold plating solution stability evaluation method, a 1 L beaker made of PP (polypropylene) resin is used as a plating tank. used. In addition, in order to remove impurities adhering to the inside of the tank, the inside of the tank was washed with aqua regia (1: 3 = nitric acid: hydrochloric acid, diluted with pure water to 50%) for 6 hours or more at room temperature before the experiment. After that, washing with water and washing with pure water were sequentially and sufficiently performed, dried at 80 ° C., and used in the experiment.
【００６０】（金めっき液安定性評価方法）金めっき液
安定性は、３条件に分類して評価した。まず（１）上記
めっき槽を使用して、めっき前に液温度を65℃に設定し
て１時間放置した時の金めっき液の安定性を評価した。
次に（２）昇温後0．36ｄｍ2／Lのめっき負荷で1時間
（65℃）めっき処理した。次いで（３）そのめっき液を
自然冷却し、室温で金めっき液を１日放置し、異常析出
物がめっき槽の底面を覆う面積の割合（槽内異常析出発
生面積（％））、すなわち異常析出成分（％）でめっき
液安定性を評価した。なお、評価基準は表１に示す通り
である。(Gold Plating Solution Stability Evaluation Method) Gold plating solution stability was evaluated by classifying into 3 conditions. First, (1) Using the above plating bath, the stability of the gold plating solution was evaluated when the solution temperature was set to 65 ° C. and left for 1 hour before plating.
Next, (2) after temperature rising, plating treatment was performed for 1 hour (65 ° C.) under a plating load of 0.36 dm 2 / L. Then, (3) the plating solution was naturally cooled, and the gold plating solution was allowed to stand at room temperature for 1 day, and the ratio of the area where abnormal deposits covered the bottom surface of the plating bath (abnormal deposition occurrence area (%) in the bath), that is, abnormal The stability of the plating solution was evaluated by the precipitation component (%). The evaluation criteria are as shown in Table 1.
【００６１】[0061]
【表１】 [Table 1]
【００６２】［皮膜外観及びめっき付き回り不良評価方
法］めっき外観、めっき付き回り不良については、電気
金めっき皮膜（0．5μｍ相当）に近い外観を標準とし
た。また、めっき付き回り性につては、めっき端部を顕
微鏡（20〜50倍相当）で目視観察して評価した。[Film Appearance and Evaluation Method for Defects with Plating] With regard to plating appearance and defects with plating, a standard appearance was close to that of an electro-gold plating film (corresponding to 0.5 μm). In addition, the roundness with plating was evaluated by visually observing the plated end portion with a microscope (corresponding to 20 to 50 times).
【００６３】［無電解金めっき液の作製及び評価］
（実施例１〜４）表２に示す組成になるように実施例１
〜４の無電解金めっき液を作製し、上述した評価方法に
基づいて評価を行った。なお、実施例１〜４は、還元剤
であるヒドロキノン濃度を３ｇ／Ｌに一定にして実験を
行った。また、析出速度促進剤である重金属塩として硝
酸タリウムとして用い、実施例１〜４の無電解金めっき
液におけるＴｌ（タリウム）イオンは、それぞれ１、
３、５、１０ｐｐｍなるようにした。[Preparation and Evaluation of Electroless Gold Plating Solution] (Examples 1 to 4) Example 1 was prepared so as to have the composition shown in Table 2.
The electroless gold plating solutions Nos. 4 to 4 were produced and evaluated based on the above-described evaluation method. In addition, in Examples 1 to 4, experiments were conducted with the concentration of the reducing agent, hydroquinone, being kept constant at 3 g / L. In addition, Tl (thallium) ions in the electroless gold plating solutions of Examples 1 to 4 were used as thallium nitrate as a heavy metal salt that is a deposition rate accelerator,
It was set to 3, 5, 10 ppm.
【００６４】析出速度、皮膜外観、めっき付き回り不良
及び金めっき液安定性について表２にまとめて示すが、
タリウムイオン濃度が１ｐｐｍで析出速度の増加が見ら
れ、未添加浴との比較で約２倍の析出速度向上が確認で
きた。また、めっき皮膜の外観は均一なレモンイエロー
で、付き回り不良の発生もなく良好であった。また、め
っき中やめっき後の金めっき液安定性も良好であった。
更に、タリウムイオンの含有量が３、５、１０ｐｐｍに
なるにしたがって、析出速度は増加し、１０ｐｐｍの添
加で０．３６μｍ／時の析出速度（未添加時の約３倍）
を示した。しかも、めっき皮膜の外観は均一なレモンイ
エローで、析出速度の増加に伴うめっき付き回り不良の
発生もなく良好であった。また、めっき中やめっき後の
液安定性も良好であった。Table 2 summarizes the deposition rate, the film appearance, the plating defect, and the stability of the gold plating solution.
When the thallium ion concentration was 1 ppm, an increase in the deposition rate was observed, and it was confirmed that the deposition rate was improved about twice as compared with the unadded bath. Moreover, the appearance of the plating film was a uniform lemon yellow color, which was good without the occurrence of sticking defects. The stability of the gold plating solution during and after plating was also good.
Furthermore, as the content of thallium ions becomes 3, 5, and 10 ppm, the deposition rate increases, and the deposition rate of 0.36 μm / hour with the addition of 10 ppm (about 3 times that without addition).
showed that. Moreover, the appearance of the plating film was a uniform lemon yellow color, which was good without the occurrence of defective plating adhesion due to an increase in the deposition rate. The liquid stability during and after plating was also good.
【００６５】[0065]
【表２】 [Table 2]
【００６６】（実施例５〜８）表３に示す組成になるよ
うに実施例５〜８の無電解金めっき液を作製し、上述し
た評価方法に基づいて評価を行った。実施例５〜８は、
還元剤であるヒドロキノン濃度を更に多い５ｇ／Ｌに一
定にして実験を行った。また、析出速度促進剤である重
金属塩として硝酸タリウムとして用い、実施例５〜８の
無電解金めっき液におけるＴｌ（タリウム）イオンは、
それぞれ１、３、５、１０ｐｐｍなるようにした。(Examples 5 to 8) Electroless gold plating solutions of Examples 5 to 8 were prepared so as to have the compositions shown in Table 3 and evaluated according to the above-described evaluation method. Examples 5 to 8
The experiment was conducted with the concentration of the reducing agent, hydroquinone, being kept constant at 5 g / L. In addition, Tl (thallium) ions in the electroless gold plating solutions of Examples 5 to 8 were used as thallium nitrate as a heavy metal salt that is a deposition rate accelerator.
It was made to be 1, 3, 5, and 10 ppm, respectively.
【００６７】析出速度、皮膜外観、めっき付き回り不良
及び金めっき液安定性について表３にまとめて示すが、
タリウムイオン濃度が１ｐｐｍで析出速度の増加が見ら
れ、実施例１と同様に未添加浴（比較例４）との比較で
約２倍の析出速度向上が確認できた。また、めっき皮膜
の外観は均一なレモンイエローで、めっき付き回り不良
の発生もなく良好であった。また、めっき中やめっき後
の金めっき液安定性も良好であった。更に、タリウムイ
オンの含有量が３、５、１０ｐｐｍになるにしたがっ
て、析出速度は増加し、ヒドロキノン５ｇ／Ｌ、タリウ
ム１０ｐｐｍ、ｐＨ７．５の条件で０．５６μｍ／時の
析出速度（未添加時の約３から４倍）を示した。しか
も、めっき皮膜の外観は均一なレモンイエローで、析出
速度の増加に伴うめっき付き回り不良の発生もなく良好
であった。また、めっき中やめっき後の液安定性も良好
であった。Table 3 summarizes the deposition rate, the film appearance, the plating defect, and the stability of the gold plating solution.
When the thallium ion concentration was 1 ppm, an increase in the deposition rate was observed, and as in Example 1, it was confirmed that the deposition rate was about doubled as compared with the non-addition bath (Comparative Example 4). Moreover, the appearance of the plating film was a uniform lemon yellow color, which was good with no occurrence of defective plating adhesion. The stability of the gold plating solution during and after plating was also good. Furthermore, as the content of thallium ions becomes 3, 5, and 10 ppm, the deposition rate increases, and the deposition rate of 0.56 μm / hour (when not added) under the conditions of hydroquinone 5 g / L, thallium 10 ppm, and pH 7.5. Of about 3 to 4 times). Moreover, the appearance of the plating film was a uniform lemon yellow color, which was good without the occurrence of defective plating adhesion due to an increase in the deposition rate. The liquid stability during and after plating was also good.
【００６８】[0068]
【表３】 [Table 3]
【００６９】（実施例９〜１２）表４に示す組成になる
ように実施例９〜１２の無電解金めっき液を作製し、上
述した評価方法に基づいて評価を行った。金めっき液組
成は、実施例５〜８と同様に、還元剤であるヒドロキノ
ンを５ｇ／L、ｐHを液安定性の良い７．５で、析出速度
促進剤としてタリウムイオンを１、３、５、１０ｐｐｍ
の条件で、めっき温度を８０℃で実験を行った。(Examples 9 to 12) The electroless gold plating solutions of Examples 9 to 12 were prepared so as to have the compositions shown in Table 4 and evaluated according to the above-described evaluation method. Similar to Examples 5 to 8, the composition of the gold plating solution was such that hydroquinone as a reducing agent was 5 g / L, pH was 7.5 with good liquid stability, and thallium ions were 1, 3, and 5 as precipitation rate accelerators. 10 ppm
The experiment was conducted at the plating temperature of 80 ° C. under the above condition.
【００７０】析出速度、皮膜外観、めっき付き回り不良
及び金めっき液安定性について表４にまとめて示すが、
めっき温度を８０℃にすると析出速度は更に速くなり、
１．０ｐｐｍの添加で約０．５μｍ／時の析出速度を示
した。また、更に添加量を多くすると１０．０ｐｐｍの
添加で１．１５μｍ／時の実用析出速度を示した。ま
た、めっき外観については、実施例９〜１２の条件では
すべて、均一なレモンイエローの外観を示し、めっき付
き回り不良や、析出ムラの発生もなく良好な結果であっ
た。金めっき液の安定性については、めっき前、めっき
中、めっき後、めっき後（１日以上）も良好な結果であ
った。Table 4 shows the deposition rate, coating appearance, defective plating, and stability of the gold plating solution.
When the plating temperature is set to 80 ° C, the deposition rate becomes faster,
The addition of 1.0 ppm showed a deposition rate of about 0.5 μm / hour. Further, when the amount added was further increased, a practical deposition rate of 1.15 μm / hour was exhibited with the addition of 10.0 ppm. Regarding the plating appearance, under all the conditions of Examples 9 to 12, a uniform lemon yellow appearance was exhibited, and there was no defective plating adhesion or occurrence of precipitation unevenness, which was a good result. Regarding the stability of the gold plating solution, good results were obtained before plating, during plating, after plating, and after plating (1 day or more).
【００７１】[0071]
【表４】 [Table 4]
【００７２】（比較例１〜４）表５に示す組成になるよ
うに比較例１〜４の無電解金めっき液を作製し、上述し
た評価方法に基づいて評価を行った。比較例１、２、３
及び４にはそれぞれ、還元剤としてヒドロキノンを０、
１、３及び５ｇ/Ｌ添加して金めっきを行った。(Comparative Examples 1 to 4) Electroless gold plating solutions of Comparative Examples 1 to 4 were prepared so as to have the compositions shown in Table 5 and evaluated according to the above-described evaluation method. Comparative Examples 1, 2, 3
Hydroquinone as a reducing agent is 0 in each of 4 and 4,
Gold plating was performed by adding 1, 3 and 5 g / L.
【００７３】析出速度、皮膜外観、めっき付き回り不良
及び金めっき液安定性について表５にまとめて示すが、
還元剤であるヒドロキノンを添加しない場合は、１時間
めっき液中に浸漬しても、ほとんど金膜厚の増加がな
く、析出が進行しない結果となった。一方、還元剤とし
てヒドロキノンを添加した場合、析出膜厚が除々に増加
し、ヒドロキノン５ｇ/Ｌで０．１５２μｍ/時（未添加
時の約２．５倍）の析出膜厚を得ることができた。Table 5 shows the deposition rate, coating appearance, defective plating, and stability of the gold plating solution.
When hydroquinone as a reducing agent was not added, even when immersed in the plating solution for 1 hour, there was almost no increase in the gold film thickness, and the result was that precipitation did not proceed. On the other hand, when hydroquinone was added as a reducing agent, the deposited film thickness gradually increased, and it was possible to obtain a deposited film thickness of 0.152 μm / hour (approximately 2.5 times that without addition) at 5 g / L hydroquinone. It was
【００７４】また、比較例２〜４の条件では、めっき皮
膜の外観は均一なレモンイエローで、付き回り不良の発
生もなく良好であった。また、めっき中やめっき後の液
安定性も良好であった。しかし、析出速度が実用的な無
電解金めっき液（約０．２〜１．０μｍ/時、又はこれ
以上）と比較して析出速度が遅い結果となった。このた
めパッケージ基板等のワイヤボンディング基板には、生
産性が悪く問題であることがわかった。Under the conditions of Comparative Examples 2 to 4, the appearance of the plating film was a uniform lemon yellow color, which was good without the occurrence of sticking defects. The liquid stability during and after plating was also good. However, the deposition rate was slower than that of a practical electroless gold plating solution (about 0.2 to 1.0 μm / hour or more). Therefore, it has been found that the wire bonding substrate such as a package substrate has a poor productivity and is a problem.
【００７５】[0075]
【表５】 [Table 5]
【００７６】（比較例５〜８）表６に示す組成になるよ
うに比較例５〜８の無電解金めっき液を作製し、上述し
た評価方法に基づいて評価を行った。析出速度、皮膜外
観、めっき付き回り不良及び金めっき液安定性について
表６にまとめて示すが、金めっき液のｐＨを１ＮのＮａ
ＯＨを使用して、それぞれ８、９、１０と変化させる
と、ｐＨ９の条件で析出速度が著しく増加し、約０．８
μｍ／時を示した。しかし、ｐＨ９と１０の条件では、
めっき液が非常に不安定で昇温中に、めっき槽内で異常
析出が発生して通常に使用することが困難な結果となっ
た。またｐH８．０の条件（比較例５）でも、めっき後
１日経過すると、めっき槽内の一部に異常析出が発生す
る結果となった。(Comparative Examples 5 to 8) Electroless gold plating solutions of Comparative Examples 5 to 8 were prepared so as to have the compositions shown in Table 6 and evaluated according to the above-described evaluation method. Table 6 summarizes the deposition rate, film appearance, poor plating adhesion and stability of the gold plating solution. The pH of the gold plating solution is 1N Na.
When OH was used and changed to 8, 9 and 10, respectively, the precipitation rate was remarkably increased under the condition of pH 9 to about 0.8.
μm / hour was shown. However, under the conditions of pH 9 and 10,
The plating solution was so unstable that abnormal precipitation occurred in the plating tank during the temperature rise, making it difficult to use normally. Even under the condition of pH 8.0 (Comparative Example 5), one day after plating, abnormal precipitation occurred in a part of the plating tank.
【００７７】更に、めっき外観については、ｐＨ８の条
件ではレモンイエローの均一な表面であったが、ｐＨ９
と１０については赤褐色の外観不良になる結果となっ
た。また、めっき付き回り性については、比較例５、
６、７の条件では問題無い結果となった。比較例８につ
いては、比較例６と同様にｐH９．０で、めっき温度を
８０℃で実験したが、めっき外観が赤褐色で悪く、液安
定性は６５℃と比較して更に悪くなり、めっき前に液中
の金イオンの消費が多く、析出速度が６５℃の条件と変
わらない結果となった。Further, regarding the plating appearance, under the condition of pH 8, it was a uniform surface of lemon yellow.
Regarding Nos. 10 and 10, the result was a reddish brown appearance defect. In addition, regarding the turning property with plating, Comparative Example 5,
Under the conditions of 6 and 7, there was no problem. Comparative Example 8 was tested at pH 9.0 and a plating temperature of 80 ° C. as in Comparative Example 6, but the plating appearance was reddish brown and the liquid stability was worse than that of 65 ° C. before plating. Moreover, the amount of gold ions in the solution was much consumed, and the result was that the deposition rate was the same as the condition of 65 ° C.
【００７８】[0078]
【表６】 [Table 6]
【００７９】以上の結果から本発明の無電解金めっき液
は、重金属塩の添加によって、還元剤であるヒドロキノ
ンの析出効率を高めることが可能となり、しかも、実用
的な析出速度（０．２〜１．０μｍ／時）が得られ、安
定性と均一なレモンイエローの皮膜外観を有する無電解
金めっきが可能であることがわかった。また、液のｐＨ
が中性付近（６〜８）で、かつ低い温度条件（６０〜８
０℃）で使用可能なため、金めっき液の安定性が低く、
大量生産が不可能なため実用化されていなかった中性で
の無電解金めっきが可能となり、適用できる材料や電子
部品等の範囲は大幅に拡大される。From the above results, the electroless gold plating solution of the present invention can increase the deposition efficiency of hydroquinone as a reducing agent by adding a heavy metal salt, and has a practical deposition rate (0.2 to It was found that electroless gold plating having stability and uniform lemon yellow film appearance was possible. Also, the pH of the liquid
Is near neutral (6 to 8) and low temperature conditions (60 to 8)
Since it can be used at 0 ° C), the stability of the gold plating solution is low,
Since mass production is impossible, neutral electroless gold plating, which has not been put into practical use, can be performed, and the range of applicable materials and electronic parts will be greatly expanded.
【００８０】[0080]
【発明の効果】以上説明したように、本発明によれば、
ｐＨ６〜８程度の中性領域において液温６０〜８０℃程
度の低温でも、充分な金の析出速度を発揮する無電解金
めっき液であって、めっき液の安定性が特に優れた無電
解金めっき液を提供することが可能になる。また、かか
る無電解金めっき液を用いた無電解金めっき方法を提供
することが可能になる。As described above, according to the present invention,
An electroless gold plating solution that exhibits a sufficient gold deposition rate even in a low temperature of about 60 to 80 ° C. in a neutral pH range of about 6 to 8 and is particularly excellent in stability of the plating solution. It becomes possible to provide a plating solution. Further, it becomes possible to provide an electroless gold plating method using such an electroless gold plating solution.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 村上 敢次 茨城県下館市大字小川1500番地 日立化成 工業株式会社下館事業所内 Ｆターム(参考） 4K022 AA02 BA03 BA31 CA07 DA03 DB01 DB05 DB06 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor, Mitsuru Makiji Hitachi Chemical, 1500 Ogawa, Shimodate City, Ibaraki Prefecture Shimodate Office of Industry Co., Ltd. F-term (reference) 4K022 AA02 BA03 BA31 CA07 DA03 DB01 DB05 DB06
Claims (14)
元剤と、重金属塩と、を含むことを特徴とする無電解金
めっき液。 【化１】 ［式中、Ｒ1は水酸基又はアミノ基を示し、Ｒ2、Ｒ3及
びＲ4はそれぞれ独立に水酸基、アミノ基、水素原子又
はアルキル基を示す。］1. An electroless gold plating solution comprising a gold salt, a reducing agent represented by the following general formula (I), and a heavy metal salt. [Chemical 1] [In the formula, R 1 represents a hydroxyl group or an amino group, and R 2 , R 3 and R 4 each independently represent a hydroxyl group, an amino group, a hydrogen atom or an alkyl group. ]
項１記載の無電解金めっき液。2. The electroless gold plating solution according to claim 1, further comprising a complexing agent.
請求項１又は２記載の無電解金めっき液。3. The electroless gold plating solution according to claim 1, further comprising a pH buffering agent.
とする請求項１〜３のいずれか一項に記載の無電解金め
っき液。4. The electroless gold plating solution according to claim 1, further comprising a metal ion masking agent.
素塩、アンチモン塩、テルル塩及びビスマス塩からなる
群より選ばれる少なくとも１つの重金属塩であることを
特徴とする請求項１〜４のいずれか一項に記載の無電解
金めっき液。5. The heavy metal salt is at least one heavy metal salt selected from the group consisting of thallium salt, lead salt, arsenic salt, antimony salt, tellurium salt and bismuth salt. The electroless gold plating solution according to any one of 1.
を特徴とする請求項１〜５のいずれか一項に記載の無電
解金めっき液。6. The electroless gold plating solution according to claim 1, wherein the heavy metal salt is a thallium salt.
は重金属有機錯体塩であることを特徴とする請求項１〜
６のいずれか一項に記載の無電解金めっき液。7. The heavy metal salt is a heavy metal inorganic compound salt or a heavy metal organic complex salt.
The electroless gold plating solution according to any one of 6 above.
００ｐｐｍとなるように前記重金属塩を含有することを
特徴とする請求項１〜７のいずれか一項に記載の無電解
金めっき液。8. The heavy metal derived from the heavy metal salt is 1 to 1.
The electroless gold plating solution according to any one of claims 1 to 7, wherein the heavy metal salt is contained at a concentration of 00 ppm.
下記一般式（II）で表される還元剤であることを特徴と
する請求項１〜８のいずれか一項に記載の無電解金めっ
き液。 【化２】 ［式中、Ｒ21は水酸基又はアミノ基を示し、Ｒ22は水素
原子又は炭素数１〜４のアルキル基を示す。］9. The reducing agent represented by the general formula (I) is:
The electroless gold plating solution according to any one of claims 1 to 8, which is a reducing agent represented by the following general formula (II). [Chemical 2] [In the formula, R 21 represents a hydroxyl group or an amino group, and R 22 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ]
する請求項１〜９のいずれか一項に記載の無電解金めっ
き液。10. The electroless gold plating solution according to claim 1, wherein the pH is 5 to 10.
る金の析出速度が０．２〜１．０μｍ／時であり、０．
３６ｄｍ2／Ｌのめっき負荷で６５℃において１時間め
っきを行った後に室温で１日放置したときの異常析出成
分が０％であることを特徴とする無電解金めっき液。11. A gold deposition rate of 0.2 to 1.0 μm / hour at a pH of 6 to 8 and a liquid temperature of 60 to 80 ° C.,
An electroless gold plating solution containing 0% of an abnormally precipitated component when plated at 65 ° C. for 1 hour under a plating load of 36 dm 2 / L and then left at room temperature for 1 day.
漬して該被めっき体表面に金被膜を形成させる無電解金
めっき方法において、前記無電解金めっき液は、請求項
１〜１１のいずれか一項に記載の無電解金めっき液であ
ることを特徴とする無電解金めっき方法。12. An electroless gold plating method in which an object to be plated is immersed in an electroless gold plating solution to form a gold coating on the surface of the object to be plated, wherein the electroless gold plating solution comprises: The electroless gold plating solution according to any one of 1.
であることを特徴とする請求項１２記載の無電解金めっ
き方法。13. The pH of the electroless gold plating solution is 6-8.
The electroless gold plating method according to claim 12, wherein
℃の前記無電解めっき液で行うことを特徴とする請求項
１２又は１３記載の無電解金めっき方法。14. The formation of the gold coating is performed at a liquid temperature of 60-80.
The electroless gold plating method according to claim 12 or 13, wherein the electroless plating solution is at a temperature of 0 ° C.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005256140A (en) * | 2004-03-15 | 2005-09-22 | C Uyemura & Co Ltd | Gold plating bath |
| JP2006111960A (en) * | 2004-09-17 | 2006-04-27 | Shinko Electric Ind Co Ltd | Non-cyanide electroless gold plating solution and process for electroless gold plating |
| JP2006249485A (en) * | 2005-03-10 | 2006-09-21 | Japan Pure Chemical Co Ltd | Gold sulfite salt aqueous solution for gold plating |
| US7300501B2 (en) | 2004-04-05 | 2007-11-27 | Nikko Materials Co., Ltd. | Electroless gold plating liquid |
| JP2007308796A (en) * | 2006-04-18 | 2007-11-29 | Hitachi Chem Co Ltd | Electroless gold plating liquid and electroless gold plating method |
| JP2008266712A (en) * | 2007-04-19 | 2008-11-06 | Hitachi Chem Co Ltd | Electroless gold plating method for electronic component, and electronic component |
-
2002
- 2002-03-15 JP JP2002072824A patent/JP2003268559A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005256140A (en) * | 2004-03-15 | 2005-09-22 | C Uyemura & Co Ltd | Gold plating bath |
| US7300501B2 (en) | 2004-04-05 | 2007-11-27 | Nikko Materials Co., Ltd. | Electroless gold plating liquid |
| JP2006111960A (en) * | 2004-09-17 | 2006-04-27 | Shinko Electric Ind Co Ltd | Non-cyanide electroless gold plating solution and process for electroless gold plating |
| JP2006249485A (en) * | 2005-03-10 | 2006-09-21 | Japan Pure Chemical Co Ltd | Gold sulfite salt aqueous solution for gold plating |
| JP2007308796A (en) * | 2006-04-18 | 2007-11-29 | Hitachi Chem Co Ltd | Electroless gold plating liquid and electroless gold plating method |
| JP2008266712A (en) * | 2007-04-19 | 2008-11-06 | Hitachi Chem Co Ltd | Electroless gold plating method for electronic component, and electronic component |
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