JP3566498B2 - Displacement gold plating bath - Google Patents

Description

［ここで、Ｘは−Ｈ、−ＮＨ_２ 又は−ＮＨ−ＣＯ−ＣＨ_３ を表し、Ｙは−Ｈ又は−ＣＯＯＨを表す。ただし、Ｘ及びＹが同時に−Ｈであることはない。］
で表されるメルカプトカルボン酸類の金錯体及びそれらの金化合物のアルカリ金属塩若しくはアンモニウム塩から選ばれた１種又は２種以上が適宜用いられる。
【０００９】
該メルカプトカルボン酸類の金錯体の中では、メルカプトコハク酸、システイン、アセチルシステイン等の金錯体が最も好適に用いることができる。アルカリ金属塩としては、ナトリウム、カリウム塩などが好ましい。
【００１０】
本願発明の金めっき浴における金の濃度は、０．１〜５０ｇ／ｌの範囲で用いられ、一層好適には２〜３０ｇ／ｌが用いられる。
【００１１】
それらの金錯体をめっき液中に安定に保持するための安定化錯化剤として、上記一般式（Ａ）で表されるメルカプトカルボン酸類又はそれらのアルカリ金属塩若しくはアンモニウム塩から選ばれた１種又は２種以上が適宜用いられる。
【００１２】
該メルカプトカルボン酸類の中で、メルカプトコハク酸、システイン、アセチルシステイン等が最も好適に用いることは、上述の金錯体におけると同じである。
【００１３】
それらのメルカプトカルボン酸類の好適な使用量は、明瞭な限界点はないが、概ね１〜１００ｇ／ｌであり、一層好適には１０〜７０ｇ／ｌが用いられる。
【００１４】
本願発明のめっき浴には、素地から溶解したニッケルイオンのめっき皮膜への影響を最小限に抑制するために、さらに下記一般式（Ｂ）及び（又は）一般式（Ｃ）から選ばれたニッケルイオン隠蔽錯化剤の１種又は２種以上が用いられる。
【００１５】
・一般式（Ｂ）
【化５】

［ここで、Ｒは単結合又はＣ_１ 〜Ｃ_４ アルキレン基を表わし、該Ｒの水素は、その半数までの範囲で、任意の位置でヒドロキシル基及び（又は）カルボキシル基により置換されていてよい。Ｘは水素（ただし、Ｒが単結合の場合は除く。）、カルボキシル基又はＣＨ_２ ＯＨ基を表わす。］
で表されるオキシカルボン酸若しくは多価カルボン酸又はそれらのアルカリ金属塩若しくはアンモニウム塩。
【００１６】
・一般式（Ｃ）
【化６】

［ここで、Ｘは−ＣＨ_２ ＣＯＯＨ又は−Ｃ_２ Ｈ_４ ＣＯＯＨを表し、Ｙは−ＣＨ_２ ＣＯＯＨ若しくは−Ｃ_２ Ｈ_４ ＣＯＯＨ又は−ＣＨ_２ ＯＨを表し、Ｚは−ＣＨ_２ ＣＯＯＨ若しくは−Ｃ_２ Ｈ_４ ＣＯＯＨ又は−ＣＨ_２ ＯＨ又は水素を表す。Ａは単結合、−ＣＨ（０Ｈ）−又は−ＣＨ_２ −Ｎ（ＣＨ_２ ＣＯＯＨ）−ＣＨ_２ −を表し、Ｂは水素を表すか、又はＡが単結合の場合にはＢ同志がメチレン基を介して結合し飽和６員環を形成してもよい。］
で表されるアミンカルボン酸又はそれらのアルカリ金属塩若しくはアンモニウム塩。
【００１７】
上記一般式（Ｂ）で表されるオキシカルボン酸又は多価カルボン酸として、グリコール酸、マロン酸、琥珀酸、乳酸、リンゴ酸、酒石酸、クエン酸又はグルコン酸などが好適に用いられる。アルカリ金属塩としては、ナトリウム、カリウム塩などが好ましい。
【００１８】
上記一般式（Ｃ）で表されるアミンカルボン酸として、エチレンジアミン四酢酸、１，２−ジアミノシクロヘキサン−Ｎ，Ｎ，Ｎ’，Ｎ’−四酢酸、１，３−ジアミノヒドロキシプロパン−Ｎ，Ｎ，Ｎ’，Ｎ’−四酢酸、、ジエチルトリアミン−Ｎ，Ｎ，Ｎ’，Ｎ”，Ｎ”−五酢酸、Ｎ，Ｎ−ビス（２−ヒドロキシエチル）グリシン、イミノ二酢酸、ニトリロ三酢酸、ニトリロ三プロピオン酸などが好適に用いられる。アルカリ金属塩としては、ナトリウム、カリウム塩などが好ましい。
【００１９】
即ち、置換型金めっき浴においては、金の析出は素地の溶出と引き換えに生じるため、浴の使用とともに素地金属のイオンが浴中に蓄積してくる。これにともなって、浴の不安定化やめっき皮膜の白色化あるいははんだ付け性の劣化などの問題が生じる。
【００２０】
このような問題に対して、金以外の金属に対する隠蔽錯化剤を添加することは、例えば、既に亜硫酸塩を錯化剤とする浴において、特開平０６−２２８７６１にＥＤＴＡを添加する例が開示されている。しかしながら、メルカプトカルボン酸類を金の錯化剤とする浴における上述の隠蔽錯化剤の添加の効果は格別であり、後に実施例において説明を加えるごとく、隠蔽錯化剤を添加したメルカプトカルボン酸類の浴の浴寿命はシアン浴に匹敵するものであったのである。
【００２１】
即ち、メルカプトカルボン酸類を金の錯化剤とする浴において、該隠蔽錯化剤が亜硫酸塩を錯化剤とする浴に比較して格別の効果を示す理由については完全に解明されているわけではないが、メルカプトカルボン酸類を金の錯化剤とする浴においては、該隠蔽錯化剤がニッケルの主錯化剤となり、金の錯化剤として添加されている該メルカプトカルボン酸類がニッケルの補助錯化剤として作用し、上述の格別の効果を発揮しているのではないかと想像される。亜硫酸塩を金の錯化剤とする浴では、 亜硫酸イオンにこのような補助隠蔽錯化剤としての効果が全く期待できないのである。
【００２２】
そのような格別の効果を発揮させるための、該隠蔽錯化剤の使用量は１〜１００ｇ／ｌであり、一層好適には、１〜２０ｇ／ｌが用いられる。
【００２３】
使用量が不足の場合には、めっき皮膜の白色化やはんだ付け性の劣化を防止するという所期の目的を達成せず、過剰の添加は金めっき被膜の色調を茶色化し、光沢を鈍くさせる。
【００２４】
さらに、本願発明の第２の様態は、該めっき浴にさらに、２−メルカプトベンゾチアゾール、６−エトキシ−２−メルカプトベンゾチアゾール及びそれらのシクロヘキシルアミン塩又は−Ｓ−プロパンスルホン酸ナトリウム塩、ジチゾン又は１，１０−フェナントロリン塩化物を添加から選ばれる化合物を浴安定剤として添加してなることを特徴とする非シアンの置換型無電解金めっき浴を用いることである。
【００２５】
無電解金めっきはニッケルめっき上に施されることが多いが、ニッケルめっきのさらに下地は銅あるいは銅合金であることが多い。ニッケルめっきには通常ピンホールが存在する故に、めっき浴中の金はニッケルばかりてなく、素地の銅とも置換反応を生起し、もって、ピンホールの周辺の金めっき被膜に銅が検出され（正木ら、表面技術協会第９３回講演大会 要旨集Ｐ１６４）、半田付け性に悪影響を及ぼしたり、浴中に銅イオンを蓄積させることによって、めっき浴の劣化を招いたりする。
【００２６】
上記化合物は銅に対するインヒビターとして作用し、もって浴中の金の素地銅との置換を抑制し、該めっき浴の寿命の延長に効果を発揮するのである。還元型の金めっき浴においては、ごく僅かに起こり得る置換反応を防止するためにこのようなインヒビターが効果を示す例が、例えば、亜硫酸−チオ硫酸を錯化剤とする還元型金めっき浴において、Ｋａｔｏらの報告（Ｍ．Ｋａｔｏ ｅｔ．ａｌ．Ｐｒｏｃ．８２ｔｈ ＡＥＳＦ Ｔｅｃｈｎｉｃａｌ Ｃｏｎｆｅｒｅｎｃｅ，ｐ８０５（１９９５））に認められる。しかしながら、置換反応によって進行する置換型金めっき浴において、このようなインヒビター効果が認められることは予想外のことであった。事実、これまで、 置換型金めっき浴、特にメルカプトカルボン酸類を錯化剤とする浴に適用された例を見なかったのである。
【００２７】
該インヒビターの使用量は、０．１〜１０００ｐｐｍであり、一層好ましくは１〜１００ｐｐｍである。使用量の不足は、めっき浴の寿命を延長するという所期の効果を得ることができず、使用量の過剰は、めっき速度の低下を招く。
【００２８】
本願のめっき浴のｐＨは１〜１２の範囲で適宜調整するが、さらに好適には４〜１０の範囲に調整する。
【００２９】
ｐＨの調整には公知の酸又はアルカリを用いることができるが、一般的には酸としては硫酸を、アルカリとしては水酸化カリウム、水酸化ナトリウム及び（又は）アンモニアを用いる。
【００３０】
該めっき浴は浴温５０〜９５℃で用いるが、さらに好適には７０〜９５℃で用いる。
【００３１】
該めっき浴は、特に電気及び無電解ニッケルめっきを下地として用いたときの浴安定性を向上させたものであるが、その実施においてはニッケルめっき上に限定されるものではなく、ニッケル、銀、錫、パラジウム等の金属及びそれらのめっき皮膜或いは黄銅、４２アロイなどの金属素地上にも適用が可能である。
【００３２】
【実施例】
以下、実施例によって本発明を具体的に説明するが、本発明は下記数例の実施例に限定されるものではない。
【００３３】
比較例１
比較例として隠蔽錯化剤を含んだ下記（ａ）の亜硫酸を錯化剤とするめっき浴を用いて無電解ニッケルめっき上にめっきを施し、めっき浴の経時劣化試験を行った。浴の評価は、得られためっき皮膜の外観を評価するとともに、メニスコグラフ法によって、２３０℃ではんだ付け性試験を行い、ゼロクロスタイムで評価した。結果は、比較例、実施例を含めて表１にまとめて示した。

【００３４】
比較例２
比較例として隠蔽錯化剤を含まない下記（ｂ）のメルカプトコハク酸を錯化剤とするめっき浴を用いて無電解ニッケルめっき上にめっきを施し、めっき浴の経時劣化試験を行った。結果は表１にまとめて示した。

【００３５】
実施例１
下記（ｃ）の金めっき浴を用いて比較例と同様のめっき浴の経時劣化試験を行った。結果は表１にまとめて示した。

【００３６】
実施例２
下記（ｄ）の金めっき浴を用いて比較例と同様のめっき浴の経時劣化試験を行った。結果は表１にまとめて示した。

【００３７】
実施例３
下記（ｅ）の金めっき浴を用いて比較例と同様のめっき浴の経時劣化試験を行った。結果は表１にまとめて示した。

【００３８】
実施例４
下記（ｆ）の金めっき浴を用いて比較例と同様のめっき浴の経時劣化試験を行った。結果は表１にまとめて示した。

【００３９】
実施例５
下記（ｇ）の金めっき浴を用いて比較例と同様のめっき浴の経時劣化試験を行った。結果は表１にまとめて示した。

【００４０】
実施例６
下記（ｈ）の金めっき浴を用いて比較例と同様のめっき浴の経時劣化試験を行った。結果は表１にまとめて示した。

【００４１】
実施例７：
下記（ｉ）の金めっき浴を用いて比較例と同様のめっき浴の経時劣化試験を行った。結果は表１にまとめて示した。

【００４２】
実施例８
下記（ｊ）の金めっき浴を用いて４２アロイ素地上に比較例と同様のめっき浴の経時劣化試験を行った。結果は表１にまとめて示した。

【００４３】
表１に経時劣化試験の結果を示した。実施例１〜８の本願発明の浴においては、経時２ターン後においても得られた皮膜の白色化や被膜のはんだ付け性の劣化は認められず、比較例１の隠蔽錯化剤を含んだ亜硫酸を錯化剤とする浴及び比較例２の隠蔽錯化剤を含まないメルカプトカルボン酸を錯化剤とする浴に比べて、格段に良好な経時特性を示した。
【００４４】
【表１】

【００４５】
【発明の効果】
本発明の非シアンの置換型無電解金めっき浴は、劣化の少ない非シアンの置換型無電解金めっき浴であり、本願の浴の発明によって、これまで浴寿命が短いことから遅れていた金めっき浴の非シアン浴への転換を容易ならしめるものである。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a plating technique, and particularly to a non-cyan substitutional electroless gold plating bath.
[0002]
[Prior art]
Gold plating is performed using each method of electroplating, substitution type electroless plating, and reduction type electroless plating. In any of these methods, a bath using a gold cyanide complex is mainly used. However, in recent years, a bath using a gold sulfite complex as a non-cyanide bath has been industrially used due to pollution and environmental problems. .
[0003]
Regarding substitutional electroless gold plating, as a non-cyan bath, a method using a gold sulfite complex has been widely studied and industrially performed, but since the stability of the plating bath is inferior to that of the cyan bath, There is a disadvantage that it is not widely used industrially.
[0004]
In recent years, various studies have been made on baths using complexing agents other than sulfurous acid. For example, Japanese Patent Application Laid-Open No. 05-156460 discloses a bath using mercaptosuccinic acid (thiomalic acid) as a complexing agent. The inventors of the present application have also reported on a bath in which mercaptosuccinic acid and acetylcysteine were co-added as complexing agents in order to further stabilize the bath (Preliminary collection P164 of the 93rd Annual Conference of Surface Technology Association). 1996)).
[0005]
However, despite these efforts, these non-cyan baths have a shorter bath life compared to cyan baths and have not achieved the properties widely used industrially.
[0006]
[Problems to be solved by the invention]
In view of the above circumstances, an object of the present invention is to develop a non-cyanide substitutional gold plating bath having a bath life comparable to that of a cyanide bath, thereby solving the pollution and environmental problems in the substitutional gold plating bath.
[0007]
[Means for Solving the Problems]
The inventors of the present application contain a non-cyanide gold compound as a source of gold, a non-cyanide solution containing mercaptocarboxylic acids as a stabilizing complexing agent for gold, and further, as a masking complexing agent for nickel ions. By adding oxycarboxylic acid, dicarboxylic acid, amine carboxylic acid, etc., it was found that a non-cyanide substituted gold plating bath having a bath life comparable to that of a cyanide bath was obtained. It came to be solved.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
That is, in the present invention, gold plating can be obtained technically using a cyan gold complex as a supply source of gold. However, due to environmental and pollution issues, cyan complexes are not preferred, and non-cyan gold is not preferred. Compounds, ie, gold chloride, gold sulfite, gold thiosulfate and the following general formula (A)
Embedded image

[Wherein, X is -H, represents -NH ₂ or -NH-CO-CH _3, Y represents -H or -COOH. However, X and Y are not simultaneously -H. ]
One or two or more selected from a gold complex of a mercaptocarboxylic acid represented by the formula and alkali metal salts or ammonium salts of those gold compounds are appropriately used.
[0009]
Among the gold complexes of mercaptocarboxylic acids, gold complexes such as mercaptosuccinic acid, cysteine, and acetylcysteine can be most preferably used. As the alkali metal salt, a sodium or potassium salt is preferable.
[0010]
The concentration of gold in the gold plating bath of the present invention is used in the range of 0.1 to 50 g / l, more preferably 2 to 30 g / l.
[0011]
As a stabilizing complexing agent for stably keeping the gold complex in a plating solution, one selected from mercaptocarboxylic acids represented by the above general formula (A) or alkali metal salts or ammonium salts thereof. Alternatively, two or more kinds are appropriately used.
[0012]
Among the mercaptocarboxylic acids, mercaptosuccinic acid, cysteine, acetylcysteine and the like are most preferably used as in the above-mentioned gold complex.
[0013]
The preferred amount of these mercaptocarboxylic acids is not limited, but is generally about 1 to 100 g / l, and more preferably 10 to 70 g / l.
[0014]
The plating bath of the present invention further includes a nickel selected from the following general formulas (B) and / or (C) in order to minimize the effect of nickel ions dissolved from the substrate on the plating film. One or more ion masking complexing agents are used.
[0015]
・ General formula (B)
Embedded image

[Wherein, R represents a single bond or a C ₁ -C ₄ alkylene group, and the hydrogen of R may be substituted at any position by a hydroxyl group and / or a carboxyl group in up to half the number thereof. . X represents hydrogen (except when R is a single bond), a carboxyl group or a CH ₂ OH group. ]
Or an alkali metal salt or an ammonium salt thereof.
[0016]
・ General formula (C)
Embedded image

[Wherein, X represents a _-CH 2 COOH or _-C 2 _H 4 COOH, Y represents _-CH 2 COOH or _-C 2 _H 4 COOH or _-CH 2 OH, Z is _-CH 2 COOH or -C It represents a ₂ H ₄ COOH or _-CH 2 OH or hydrogen. A represents a single bond, —CH (0H) — or —CH ₂ —N (CH ₂ COOH) —CH ₂ —, B represents hydrogen, or when A is a single bond, B is a methylene group And may form a saturated 6-membered ring. ]
Or an alkali metal salt or an ammonium salt thereof.
[0017]
As the oxycarboxylic acid or polycarboxylic acid represented by the general formula (B), glycolic acid, malonic acid, succinic acid, lactic acid, malic acid, tartaric acid, citric acid, gluconic acid, and the like are suitably used. As the alkali metal salt, a sodium or potassium salt is preferable.
[0018]
Examples of the amine carboxylic acid represented by the general formula (C) include ethylenediaminetetraacetic acid, 1,2-diaminocyclohexane-N, N, N ', N'-tetraacetic acid, and 1,3-diaminohydroxypropane-N, N , N ', N'-tetraacetic acid, diethyltriamine-N, N, N', N ", N" -pentaacetic acid, N, N-bis (2-hydroxyethyl) glycine, iminodiacetic acid, nitrilotriacetic acid And nitrilotripropionic acid are preferably used. As the alkali metal salt, a sodium or potassium salt is preferable.
[0019]
That is, in the substitutional gold plating bath, gold deposition occurs in exchange for the elution of the base material, so that ions of the base metal accumulate in the bath as the bath is used. Along with this, problems such as instability of the bath, whitening of the plating film or deterioration of the solderability occur.
[0020]
With respect to such a problem, the addition of a concealing complexing agent for metals other than gold is disclosed, for example, in JP-A-06-228761 in a bath in which a sulfite is already used as a complexing agent. Have been. However, the effect of the addition of the above-described concealing complexing agent in a bath using a mercaptocarboxylic acid as a complexing agent for gold is remarkable. The bath life was comparable to that of the cyan bath.
[0021]
That is, the reason why the concealing complexing agent has a remarkable effect in a bath using a mercaptocarboxylic acid as a complexing agent for gold as compared with a bath using a sulfite as a complexing agent has been completely elucidated. However, in a bath using a mercaptocarboxylic acid as a complexing agent for gold, the masking complexing agent becomes a main complexing agent for nickel, and the mercaptocarboxylic acid added as a complexing agent for gold contains nickel. It is assumed that it acts as an auxiliary complexing agent and exerts the above-mentioned special effects. In a bath using sulfite as a complexing agent for gold, sulfite ions cannot be expected to have any effect as such an auxiliary masking complexing agent.
[0022]
The amount of the concealing complexing agent to exert such a special effect is 1 to 100 g / l, more preferably 1 to 20 g / l.
[0023]
If the amount used is insufficient, the intended purpose of preventing the whitening of the plating film and the deterioration of the solderability will not be achieved, and excessive addition will make the color tone of the gold plating film brown and dull the gloss. .
[0024]
Further, a second aspect of the present invention is that the plating bath further comprises 2-mercaptobenzothiazole, 6-ethoxy-2-mercaptobenzothiazole and their cyclohexylamine salt or -S-propanesulfonic acid sodium salt, dithizone or A non-cyan substitutional electroless gold plating bath characterized in that a compound selected from the addition of 1,10-phenanthroline chloride is added as a bath stabilizer.
[0025]
Electroless gold plating is often applied on nickel plating, but the underlying layer of nickel plating is often copper or copper alloy. Since nickel plating usually has pinholes, the gold in the plating bath causes a substitution reaction not only with nickel but also with the underlying copper, so that copper is detected in the gold plating film around the pinholes (Masaki Et al., The 93rd Annual Meeting of the Surface Technology Association of Japan, P164), which has an adverse effect on solderability and causes deterioration of the plating bath by accumulating copper ions in the bath.
[0026]
The compound acts as an inhibitor for copper, thereby suppressing the replacement of gold in the bath with the base copper and exerting an effect on extending the life of the plating bath. In a reduction-type gold plating bath, an example in which such an inhibitor exhibits an effect to prevent a substitution reaction that can occur only slightly is, for example, in a reduction-type gold plating bath using sulfurous acid-thiosulfuric acid as a complexing agent. Kato et al. (M. Kato et al. Proc. 82th AESF Technical Conference, p805 (1995)). However, it was unexpected that such an inhibitory effect was observed in a substitution-type gold plating bath that proceeds by a substitution reaction. As a matter of fact, there has been no example of application to a substitution type gold plating bath, particularly a bath using a mercaptocarboxylic acid as a complexing agent.
[0027]
The amount of the inhibitor to be used is 0.1 to 1000 ppm, more preferably 1 to 100 ppm. Insufficient use cannot provide the desired effect of extending the life of the plating bath, and excessive use results in a decrease in plating rate.
[0028]
The pH of the plating bath of the present invention is appropriately adjusted in the range of 1 to 12, but is more preferably adjusted in the range of 4 to 10.
[0029]
For adjusting the pH, a known acid or alkali can be used. Generally, sulfuric acid is used as the acid, and potassium hydroxide, sodium hydroxide and / or ammonia are used as the alkali.
[0030]
The plating bath is used at a bath temperature of 50 to 95 ° C, more preferably at 70 to 95 ° C.
[0031]
The plating bath has improved bath stability particularly when electric and electroless nickel plating is used as a base, but is not limited to nickel plating in the practice, and nickel, silver, The present invention is also applicable to metals such as tin and palladium and their plating films or metal substrates such as brass and 42 alloy.
[0032]
【Example】
Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to the following several Examples.
[0033]
Comparative Example 1
As a comparative example, plating was carried out on the electroless nickel plating using a plating bath containing a concealing complexing agent and using a sulfurous acid as a complexing agent as shown in the following (a), and a aging test of the plating bath was performed. The bath was evaluated by evaluating the appearance of the obtained plating film, performing a solderability test at 230 ° C. by a meniscograph method, and evaluating at zero cross time. The results are collectively shown in Table 1 including Comparative Examples and Examples.

[0034]
Comparative Example 2
As a comparative example, plating was performed on the electroless nickel plating using a plating bath containing no mercaptosuccinic acid of the following (b) containing no masking complexing agent as a complexing agent, and a aging test of the plating bath was performed. The results are summarized in Table 1.

[0035]
Example 1
Using the following gold plating bath (c), the same aging deterioration test of the plating bath as in the comparative example was performed. The results are summarized in Table 1.

[0036]
Example 2
Using the following gold plating bath (d), the same aging test of the plating bath as in the comparative example was performed. The results are summarized in Table 1.

[0037]
Example 3
Using the following gold plating bath (e), a plating bath similar to that of the comparative example was subjected to a deterioration test with time. The results are summarized in Table 1.

[0038]
Example 4
Using the following gold plating bath (f), a plating bath similar to that of the comparative example was subjected to an aging deterioration test. The results are summarized in Table 1.

[0039]
Example 5
Using the following gold plating bath (g), the same aging deterioration test of the plating bath as in the comparative example was performed. The results are summarized in Table 1.

[0040]
Example 6
Using the following gold plating bath (h), a plating bath similar to that of the comparative example was subjected to a time-dependent deterioration test. The results are summarized in Table 1.

[0041]
Example 7:
Using the following gold plating bath (i), a plating bath was subjected to the same time deterioration test as in the comparative example. The results are summarized in Table 1.

[0042]
Example 8
Using the gold plating bath shown in (j) below, the same aging deterioration test of the plating bath as in the comparative example was performed on a 42 alloy substrate. The results are summarized in Table 1.

[0043]
Table 1 shows the results of the aging test. In the baths of the present invention of Examples 1 to 8, whitening of the obtained film and deterioration of the solderability of the film were not observed even after 2 lapses of time, and the concealing complexing agent of Comparative Example 1 was contained. Compared to the bath using sulfurous acid as a complexing agent and the bath of Comparative Example 2 using a mercaptocarboxylic acid containing no concealing complexing agent as a complexing agent, it showed much better aging characteristics.
[0044]
[Table 1]

[0045]
【The invention's effect】
The non-cyanide substitutional electroless gold plating bath of the present invention is a non-cyanization substitutional electroless gold plating bath with little deterioration, and the bath invention of the present application has been delayed due to the short bath life. This facilitates the conversion of the plating bath to a non-cyan bath.

Claims (3)

Non-cyanide selected from gold sulfite, gold chloride, gold thiosulfate and a gold complex of mercaptocarboxylic acid represented by the following general formula (A) or an alkali metal salt or an ammonium salt of the gold compound as a gold source. One or more selected from mercaptocarboxylic acids represented by the following general formula (A) or alkali metal salts or ammonium salts thereof as a gold stabilizing complexing agent containing one or more gold compounds. Oxycarboxylic acid or polyvalent carboxylic acid represented by the following general formula (B) or an alkali metal salt or ammonium salt thereof and / or as a concealing complexing agent for nickel or copper ions. One or more complexing agents selected from the amine carboxylic acids represented by (C) or alkali metal salts or ammonium salts thereof; Pressurizing and characterized by comprising a non-cyanide substitution type electroless gold plating bath for matrix the matrix or copper nickel or nickel alloy-based:
・ General formula (A)

[Wherein, X is -H, represents -NH ₂ or -NH-CO-CH _3, Y represents -H or -COOH. However, X and Y are not simultaneously -H. ]
A mercaptocarboxylic acid represented by
・ General formula (B)

[Wherein R represents a single bond or a C ₁ -C ₄ alkylene group, and the hydrogen of the R may be substituted with a hydroxyl group and / or a carboxyl group at any position up to a half of the number. . X represents hydrogen (except when R is a single bond), a carboxyl group or a CH ₂ OH group. ]
Represented by an oxycarboxylic acid or a polycarboxylic acid,
・ General formula (C)

[Wherein, X represents a -CH ₂ COOH or -C ₂ H ₄ COOH, Y represents -CH ₂ COOH or -C ₂ H ₄ COOH or -CH ₂ OH, Z is -CH ₂ COOH or -C It represents a ₂ H ₄ COOH or -CH ₂ OH or hydrogen. A represents a single bond, —CH (OH) — or —CH ₂ —N (CH ₂ COOH) —CH ₂ —, B represents hydrogen, or when A is a single bond, B and And may form a saturated 6-membered ring. ]
An amine carboxylic acid represented by the formula: The compound represented by the general formula (A) is mercaptosuccinic acid, cysteine or acetylcysteine, and the compound represented by the general formula (B) is glycolic acid, malonic acid, succinic acid, lactic acid, malic acid, tartaric acid, citric acid. Acid or gluconic acid, and the compound represented by the general formula (C) is ethylenediaminetetraacetic acid, 1,2-diaminocyclohexane-N, N, N ', N'-tetraacetic acid, 1,3-diaminohydroxypropane- N, N, N ', N'-tetraacetic acid, diethyltriamine-N, N, N', N ", N" -pentaacetic acid, N, N-bis (2-hydroxyethyl) glycine, iminodiacetic acid, nitrilo The non-cyanide substitution type electroless gold plating bath according to claim 1, which is triacetic acid or nitrilotripropionic acid. Further, 2-mercaptobenzothiazole, 6-ethoxy-2-mercaptobenzothiazole and their cyclohexylamine salts or sodium -S-propanesulfonic acid sodium salt, dithizone or 1,10-phenanthroline chloride are added as bath stabilizers. The non-cyanide substitution type electroless gold plating bath according to claim 1.