JP2008174796A - Gold plating liquid and gold plating method - Google Patents

Gold plating liquid and gold plating method Download PDF

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JP2008174796A
JP2008174796A JP2007009269A JP2007009269A JP2008174796A JP 2008174796 A JP2008174796 A JP 2008174796A JP 2007009269 A JP2007009269 A JP 2007009269A JP 2007009269 A JP2007009269 A JP 2007009269A JP 2008174796 A JP2008174796 A JP 2008174796A
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gold
plating solution
gold plating
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Bunichi Mizutani
文一 水谷
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Mitsubishi Chemical Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a gold plating liquid which does not comprise toxic cyanide or the like having problems in a working environment and waste liquid treatment, has excellent chemical stability, easily treatable, and can efficiently form a gold plating film of high quality, and to provide a gold plating method using the gold plating liquid. <P>SOLUTION: The gold plating liquid comprises gold complex ions, water, and a protophilic solvent, and the content of the protophilic solvent is 55 to 90 wt.%. Also disclosed is a gold plating method using the gold plating liquid. When the content of the protophilic solvent is controlled to 55 to 90 wt.%, gold complex ions are made stable, and a gold plating film of high quality can be obtained. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は金メッキ液および金メッキ方法に関し、特に非シアン系の電解金メッキ液と、この金メッキ液を用いた電解金メッキ方法に関する。   The present invention relates to a gold plating solution and a gold plating method, and more particularly, to a non-cyan electrolytic gold plating solution and an electrolytic gold plating method using the gold plating solution.

金メッキ液としては、古くから、シアン系のメッキ液が知られている。シアン系の金メッキ液を用いると、緻密で表面平滑な優れた特性をもつ金メッキ膜を析出させることができる。しかも、シアン系金メッキ液は安定で、管理が容易なため、広く用いられている。しかしながら、シアンは毒性が強く、作業環境、廃液処理などに多くの問題点があった。   As a gold plating solution, a cyan plating solution has been known for a long time. When a cyan-based gold plating solution is used, a gold plating film having excellent characteristics such as a dense and smooth surface can be deposited. Moreover, cyan-based gold plating solutions are widely used because they are stable and easy to manage. However, cyan is highly toxic and has many problems in the working environment and waste liquid treatment.

一方、非シアンの低毒性メッキ液としては、亜硫酸金系のメッキ液が広く用いられているが、亜硫酸金系のメッキ液は、メッキ液中の亜硫酸イオンが、溶存酸素や大気中の酸素によって酸化されやすく、その結果として、液寿命が低下するなど、管理に注意を要するものであった。非水溶液系のメッキ液としては、エチレングリコールを用いたメッキ液(特開昭51−47539、特開昭51−47540)も開示されているが、酸化されやすい点は同じである。その他、アセチルシステイン金錯体などを用いるもの(特開平10−317183)やアルカンスルホン酸またはアルカノールスルホン酸を用いるもの(特開平8−41676)が開示されているが、いずれも亜硫酸金と同じく一価の金イオンを用いているので、3Au→2Au+Au3+の反応による不安定化の問題がある。 On the other hand, as a non-cyanide low toxicity plating solution, a gold sulfite-based plating solution is widely used. However, the gold sulfite-based plating solution is a solution of sulfite ions in the plating solution due to dissolved oxygen or atmospheric oxygen. It is easy to oxidize, and as a result, the life of the liquid is shortened. As a non-aqueous plating solution, a plating solution using ethylene glycol (Japanese Patent Laid-Open Nos. 51-47539 and 51-47540) is also disclosed, but it is the same in that it is easily oxidized. In addition, those using gold acetylcysteine complex (JP-A-10-317183) and those using alkanesulfonic acid or alkanolsulfonic acid (JP-A-8-41676) are disclosed. Therefore, there is a problem of destabilization due to the reaction of 3Au + → 2Au + Au 3+ .

三価の金イオンを用いるものとしては、エチレンジアミン錯体によるもの(特開2001−110832、特開2000−355792、特開2000−204496、特開平11−293487)が開示されているが、エチレンジアミンは経皮的に体内に吸収されるなど有害性の問題がある。
また、チオシアン酸を用いたもの(特開昭54−66340)も開示されているが、チオシアンが加熱により分解してシアンとなるため火災時にはシアン系と同等の危険がある。
As those using trivalent gold ions, those based on ethylenediamine complexes (Japanese Patent Laid-Open Nos. 2001-110832, 2000-335592, 2000-204496, and Japanese Patent Laid-Open No. 11-293487) are disclosed. There are harmful problems such as skin absorption.
A thiocyanic acid-based one (Japanese Patent Laid-Open No. Sho 54-66340) is also disclosed. However, since thiocyanate decomposes by heating to cyan, there is a danger equivalent to that of cyan in a fire.

そこで、ヨウ化金錯体を用いたもの(特開2004−43958、WO2006−49021)が開示されたが、いずれも、ヨウ化金錯体を安定化させるためには、微量ながらも三ヨウ素イオンの共存が不可欠であり、このため、無電解メッキ液としては成り立ち得なかった。   Then, although what used a gold iodide complex (Unexamined-Japanese-Patent No. 2004-43958, WO2006-49021) was disclosed, in order to stabilize a gold iodide complex, although it is trace amount, coexistence of a triiodide ion was also carried out. Is indispensable, and therefore cannot be realized as an electroless plating solution.

さらに、ヒダントイン系化合物を錯化剤とするもの(特開2000−355792)も開示されているが、金の濃度が高くなるとpHによっては塩析が発生するという問題があった。
特開昭51−47539 特開昭51−47540 特開平10−317183 特開平8−41676 特開2001−110832 特開2000−355792 特開2000−204496 特開平11−293487 特開昭54−66340 特開2004−43958 WO2006−49021 特開2000−355792
Further, a compound using a hydantoin compound as a complexing agent (Japanese Patent Laid-Open No. 2000-357992) is also disclosed, but there is a problem that salting out occurs depending on pH when the gold concentration is increased.
JP 51-47539 JP 51-47540 JP 10-317183 A JP-A-8-41676 JP 2001-110732 A JP 2000-355792 A JP2000-204496 JP-A-11-293487 JP 54-663340 A JP2004-43958 WO2006-49021 JP 2000-355792 A

本発明は上記従来の問題点を解決し、作業環境や廃液処理に問題を有する毒性の強いシアン等を含まず、化学的安定性に優れ、容易に取り扱うことができ、良好な膜質の金メッキ膜を効率的に形成することができる金メッキ液と、この金メッキ液を用いる金メッキ方法を提供することを目的とする。   The present invention solves the above-mentioned conventional problems, does not contain highly toxic cyan or the like having a problem in the working environment and waste liquid treatment, is excellent in chemical stability, can be easily handled, and has a good film quality. It is an object of the present invention to provide a gold plating solution capable of efficiently forming a gold plating solution and a gold plating method using the gold plating solution.

本発明者は、上記課題について鋭意検討を行った結果、金錯イオン、水、および親プロトン性溶媒を含有してなり、親プロトン性溶媒の含有量が55〜90重量%である金メッキ液は、安定で容易にメッキを行えることを見出し、本発明を完成した。
即ち、親プロトン性溶媒の含有量を55〜90重量%とすると、金錯イオンが液中で非常に安定になるので、還元剤を添加しても金錯イオンの不安定化が起こらず、良質な金メッキ膜が得られる。
本発明はこのような知見に基いて達成されたものであり、以下を要旨とする。
As a result of intensive studies on the above problems, the inventor of the present invention contains a gold complex ion, water, and a protic solvent, and a gold plating solution having a protic solvent content of 55 to 90% by weight is obtained. The present invention has been completed by finding that it can be plated stably and easily.
That is, when the content of the protic solvent is 55 to 90% by weight, the gold complex ion becomes very stable in the liquid, so that even if a reducing agent is added, the destabilization of the gold complex ion does not occur. A high-quality gold plating film can be obtained.
The present invention has been achieved on the basis of such findings, and the gist thereof is as follows.

[1] 金錯イオン、水、親プロトン性溶媒および還元剤を含有してなり、親プロトン性溶媒の含有量が55〜90重量%であることを特徴とする金メッキ液。 [1] A gold plating solution comprising a gold complex ion, water, a protic solvent and a reducing agent, wherein the content of the protic solvent is 55 to 90% by weight.

[2] 該親プロトン性溶媒が、非プロトン性極性溶媒である[1]に記載の金メッキ液。 [2] The gold plating solution according to [1], wherein the protic solvent is an aprotic polar solvent.

[3] 該親プロトン性溶媒が、ラクタム構造を有する[1]又は[2]に記載の金メッキ液。 [3] The gold plating solution according to [1] or [2], wherein the protic solvent has a lactam structure.

[4] 該親プロトン性溶媒が、N−アルキルピロリドンである[3]に記載の金メッキ液。 [4] The gold plating solution according to [3], wherein the protic solvent is N-alkylpyrrolidone.

[5] 該親プロトン性溶媒100重量%に対して水を10〜50重量%含有する[1]乃至[4のいずれかに記載の金メッキ液。 [5] The gold plating solution according to any one of [1] to [4], containing 10 to 50% by weight of water with respect to 100% by weight of the protophilic solvent.

[6] シアンを実質的に含まない[1]乃至[5]のいずれかに記載の金メッキ液。 [6] The gold plating solution according to any one of [1] to [5], which does not substantially contain cyan.

[7] 三ヨウ素イオンを実質的に含まない[1]乃至[6]のいずれかに記載の金メッキ液。 [7] The gold plating solution according to any one of [1] to [6], which does not substantially contain triiodine ions.

[8] 還元剤を0.01〜10重量%含有する[1]乃至[7]のいずれかに記載の金メッキ液。 [8] The gold plating solution according to any one of [1] to [7], containing a reducing agent in an amount of 0.01 to 10% by weight.

[9] 還元剤もしくは錯化剤としてチオ尿素を含有する[1]乃至[8]のいずれかに記載の金メッキ液。 [9] The gold plating solution according to any one of [1] to [8], which contains thiourea as a reducing agent or a complexing agent.

[10] [1]乃至[9]のいずれかに記載の金メッキ液を用いてメッキを行うことを特徴とする金メッキ方法。 [10] A gold plating method comprising performing plating using the gold plating solution according to any one of [1] to [9].

本発明によれば、比較的高濃度に液中に含まれている親プロトン性溶媒の存在により、金錯イオンが液中で高度に安定化され、この結果、シアン系金メッキ液に匹敵する性能を持ちながら、シアンの毒性を持たない安定でかつ安全性が高く、取り扱い性に優れた金メッキ液が提供される。
しかも、還元剤を選択することにより、後述の実施例1のような自己触媒型の無電解メッキも、実施例4のような置換型の無電解メッキも行うことが可能となり、メッキ処理の多様化が図れる。
According to the present invention, the presence of the protic solvent contained in the solution at a relatively high concentration stabilizes the gold complex ion in the solution, and as a result, performance comparable to that of a cyan-based gold plating solution. It is possible to provide a gold plating solution that is stable, safe, and has excellent handleability without the toxicity of cyan.
In addition, by selecting a reducing agent, it is possible to perform autocatalytic electroless plating as in Example 1 to be described later and substitutional electroless plating as in Example 4. Can be achieved.

以下に本発明の金メッキ液及び金メッキ方法の実施の形態を詳細に説明する。
本発明の金メッキ液は、金錯イオン、水、親プロトン性溶媒および還元剤を含有してなり、親プロトン性溶媒の含有量が55〜90重量%であることを特徴とする金メッキ液である。
Hereinafter, embodiments of the gold plating solution and the gold plating method of the present invention will be described in detail.
The gold plating solution of the present invention is a gold plating solution comprising a gold complex ion, water, a protic solvent and a reducing agent, wherein the content of the protic solvent is 55 to 90% by weight. .

まず、このような組成を有する本発明の金メッキ液の作用機構について説明する。
本発明の金メッキ液においては、必須成分である親プロトン性溶媒が55重量%以上存在することにより、次のような機構で金錯イオンが安定となる。
例えば、ヨウ化金錯イオンの場合、金の析出は、

Figure 2008174796
の反応により起こるので、三ヨウ素イオンが一定量以上ないとヨウ化金錯イオンが安定に存在できないのに対し、親プロトン性溶媒が55重量%以上存在する場合は、上記反応のAu(メッキの前駆体である金イオン)が、親プロトン性溶媒により強く溶媒和して安定になり、
Figure 2008174796
の反応が抑止されている。 First, the action mechanism of the gold plating solution of the present invention having such a composition will be described.
In the gold plating solution of the present invention, the presence of 55 wt% or more of the protic solvent, which is an essential component, stabilizes the gold complex ion by the following mechanism.
For example, in the case of gold iodide complex ions, the precipitation of gold is
Figure 2008174796
Since the gold iodide complex ion cannot exist stably unless a certain amount of triiodine ions exceeds a certain amount, the Au + (plating) of the above reaction is present when the protophilic solvent is present in an amount of 55% by weight or more. The gold ion which is the precursor of
Figure 2008174796
The reaction is suppressed.

このように、還元剤を加えてもメッキ液が安定となり、良質の無電解メッキ液が得られる。   Thus, even if a reducing agent is added, the plating solution becomes stable, and a high-quality electroless plating solution can be obtained.

本発明の金メッキ液において、金錯イオンの種類は特に限定されないが、ヨウ化金錯イオン、塩化金錯イオンなどのハロゲンアニオンを配位子とする錯イオンが好ましく、ヨウ化金錯イオンが特に好ましい。金錯イオンは、1種を単独で用いてもよく、2種以上を混合して用いてもよい。   In the gold plating solution of the present invention, the type of gold complex ions is not particularly limited, but complex ions having a halogen anion such as a gold iodide complex ion and a gold chloride complex ion as a ligand are preferable, and a gold iodide complex ion is particularly preferable. preferable. A gold complex ion may be used individually by 1 type, and 2 or more types may be mixed and used for it.

金メッキ液中の金錯イオンの含有量は、金錯イオンが液中に安定に溶解していて、メッキが良好にできる範囲であれば特に制限は無いが、金換算含有量として、好ましくは0.01%〜50重量%、より好ましくは0.1〜30重量%、さらに好ましくは0.5〜10重量%、特に好ましくは0.8〜5重量%である。   The content of the gold complex ions in the gold plating solution is not particularly limited as long as the gold complex ions are stably dissolved in the solution and the plating can be satisfactorily performed, but the content in terms of gold is preferably 0. It is 0.01% to 50% by weight, more preferably 0.1 to 30% by weight, still more preferably 0.5 to 10% by weight, and particularly preferably 0.8 to 5% by weight.

本発明で用いる溶媒は、金イオンと強く溶媒和する親プロトン性溶媒である。親プロトン性溶媒は、塩基性の溶媒であり、エチレンジアミン、アンモニア、ホルムアミドなどの両性溶媒、および、ジメチルホルムアミド、ジメチルスルホキシド、N−メチルピロリドン、ヘキサメチルホスホルアミド、ピリジン、テトラヒドロフランなどの非プロトン性溶媒が例示できる。親プロトン性溶媒は、1種を単独で用いてもよく、2種以上を混合して用いてもよい。   The solvent used in the present invention is a protic solvent that strongly solvates with gold ions. The protic solvent is a basic solvent, and is an amphoteric solvent such as ethylenediamine, ammonia, formamide, and aprotic solvents such as dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, hexamethylphosphoramide, pyridine, and tetrahydrofuran. A solvent can be illustrated. A protic solvent may be used individually by 1 type, and 2 or more types may be mixed and used for it.

この中でも、極性の大きい非プロトン性溶媒が好ましく、ラクタム構造を有するものがさらに好ましい。
ラクタム構造を有するものとしては、水と自由に混和する、アルキル基の炭素数が1〜3のN−アルキルピロリドンが好ましく、N−メチルピロリドンが特に好ましい。
Among these, highly polar aprotic solvents are preferable, and those having a lactam structure are more preferable.
Those having a lactam structure are preferably N-alkylpyrrolidone having 1 to 3 carbon atoms in an alkyl group, which is freely miscible with water, and particularly preferably N-methylpyrrolidone.

金メッキ液中の親プロトン性溶媒の含有量は、金錯イオンの安定化のために、55重量%以上であり、70重量%以上が好ましい。また、溶質を十分に溶解させるためには水を一定量以上含有する必要があることから、親プロトン性溶媒の含有量は90重量%以下であり、85重量%以下が好ましい。   The content of the prophilic solvent in the gold plating solution is 55% by weight or more, and preferably 70% by weight or more for stabilizing the gold complex ion. Moreover, since it is necessary to contain a certain amount or more of water in order to sufficiently dissolve the solute, the content of the protophilic solvent is 90% by weight or less, preferably 85% by weight or less.

また、金メッキ液中の水の含有量は、親プロトン性溶媒100重量%に対して、好ましくは10重量%以上より好ましくは15重量%以上、さらに好ましくは20重量%以上である。水の含有量が少ないとメッキ液が不均一となる可能性がある。また好ましくは50重量%以下、より好ましくは45重量%以下、更に好ましくは40重量%以下、特に好ましくは35重量%以下である。水の含有量が多いとメッキ膜の表面が粗くなる場合がある。   The content of water in the gold plating solution is preferably 10% by weight or more, more preferably 15% by weight or more, and still more preferably 20% by weight or more with respect to 100% by weight of the protic solvent. If the water content is low, the plating solution may become non-uniform. Further, it is preferably 50% by weight or less, more preferably 45% by weight or less, still more preferably 40% by weight or less, and particularly preferably 35% by weight or less. If the water content is large, the surface of the plating film may become rough.

本発明の金メッキ液は、メッキ性能に悪影響を及ばさない限り、他の非水溶媒を含んでも良い。他の非水溶媒は、水および親プロトン性溶媒と混和するものであれば特に制限はなく、メッキ液の粘度や表面張力等の特性付与のため適宜選択して使用することができる。さらに、他の非水溶媒は2種以上添加しても良い。     The gold plating solution of the present invention may contain other nonaqueous solvents as long as the plating performance is not adversely affected. The other non-aqueous solvent is not particularly limited as long as it is miscible with water and a prophilic solvent, and can be appropriately selected and used for imparting properties such as the viscosity and surface tension of the plating solution. Further, two or more other nonaqueous solvents may be added.

また、本発明の金メッキ液は金錯イオンを含むが、この金錯イオンがヨウ化金錯イオンであっても、三ヨウ素イオンは実質的に含まない。これは前述の如く、親プロトン性溶媒の存在で2Au+4I→2Au+I +Iの反応が抑止されるためと考えられる。
ヨウ化金錯イオンを含むメッキ液は、通常、例えば、特開2004−43958、WO2006−49021のように、ヨウ素、ヨウ化物イオンを含む液に金を溶解して調製することができるが、調製した液が一定量以上の三ヨウ素イオンを含まないと、ヨウ化金錯イオンが不安定で、金が析出してしまう。それに対して、本発明では、親プロトン性溶媒の含有量を65重量%以上にすることで、還元剤によって三ヨウ素イオンを全てヨウ化物イオンに還元しても、ヨウ化金錯イオンが安定に存在するようになる。
なお、三ヨウ素イオンを実質的に含まなければ、金源が金であることは必須ではなく、塩化金酸であっても、亜硫酸金であってもよい。他の金錯イオンの場合も金錯イオンが安定に保たれるのでメッキ性能は向上する。
The gold plating solution of the present invention contains a gold complex ion, but even if this gold complex ion is a gold iodide complex ion, it does not substantially contain a triiodine ion. This is presumably because the reaction of 2Au + + 4I → 2Au + I 3 + I is suppressed in the presence of the protic solvent as described above.
A plating solution containing a gold iodide complex ion can be usually prepared by dissolving gold in a solution containing iodine or iodide ions, as disclosed in, for example, JP-A-2004-43958 and WO2006-49021. If the liquid does not contain a certain amount or more of triiodine ions, the gold iodide complex ions are unstable and gold is deposited. On the other hand, in the present invention, by setting the content of the protophilic solvent to 65% by weight or more, even if all the triiodine ions are reduced to iodide ions by the reducing agent, the gold iodide complex ions are stabilized. It comes to exist.
If the triiodine ion is not substantially contained, it is not essential that the gold source is gold, and it may be chloroauric acid or gold sulfite. In the case of other metal complex ions, the metal complex ions are kept stable, so that the plating performance is improved.

本発明のメッキ液は、無電解メッキ液として還元剤を配合する。還元剤の種類は、一般的に無電解メッキ液に使用されているものであれば限定はない。例えば、チオ尿素やアスコルビン酸が例示できる。この中でも、チオ尿素は、還元作用とともに補助錯化剤の作用も有するのでより好ましい。   The plating solution of the present invention contains a reducing agent as an electroless plating solution. The kind of reducing agent is not limited as long as it is generally used in electroless plating solutions. For example, thiourea and ascorbic acid can be exemplified. Among these, thiourea is more preferable because it has an action of an auxiliary complexing agent as well as a reducing action.

この場合、本発明の金メッキ液中の還元剤の含有量としては、好ましくは0・01重量%以上、特に好ましくは0.1重量%以上である。また、好ましくは10重量%以下、特に好ましくは5重量%以下である。還元剤の含有量が少な過ぎると膜を形成するに十分な量のAuの還元が行えず、多過ぎると還元力が強すぎてメッキ液が不安定になる。   In this case, the content of the reducing agent in the gold plating solution of the present invention is preferably 0.01% by weight or more, particularly preferably 0.1% by weight or more. Further, it is preferably 10% by weight or less, particularly preferably 5% by weight or less. If the content of the reducing agent is too small, a sufficient amount of Au cannot be reduced to form a film. If the content is too large, the reducing power is too strong and the plating solution becomes unstable.

還元剤としてアスコルビン酸を用いると共に還元剤ないし錯化剤としてチオ尿素を併用する場合、金メッキ液中のアスコルビン酸の含有量が0.1〜5重量%、チオ尿素の含有量が0.01〜10重量%となるように配合することが好ましい。   When ascorbic acid is used as the reducing agent and thiourea is used in combination as the reducing agent or complexing agent, the content of ascorbic acid in the gold plating solution is 0.1 to 5% by weight, and the content of thiourea is 0.01 to It is preferable to mix | blend so that it may become 10 weight%.

また、本発明の金メッキ液には、金錯イオン、親プロトン性溶媒、水以外の各種の添加剤を添加して、形成される金メッキ膜の特性を向上させることが可能である。このような添加剤としては本発明の所期の目的を妨げない限り、これまでのシアン系、亜硫酸系、およびヨウ化金系のメッキ液で用いられていた添加剤およびそれ以外の物質の中から選択する1種以上の物質を添加して用いることができる。   Moreover, it is possible to add the various additives other than a gold complex ion, a prophilic solvent, and water to the gold plating solution of this invention, and to improve the characteristic of the gold plating film formed. As such an additive, as long as it does not interfere with the intended purpose of the present invention, the additive used in the conventional cyan, sulfite, and gold iodide plating solutions and other substances may be used. One or more substances selected from the above can be added and used.

本発明の金メッキ液は、55重量%以上の親プロトン性溶媒により金の析出が抑制されているので、非常に安定である。このため、さらに1種以上の金属を追加して、合金メッキを行うことも容易である。銀、銅がこの溶液によく溶解することが知られているが、溶解しうる限り、それ以外の金属であってもさしつかえない。その場合には、合金メッキを良好にするため、さらに添加剤を用いることもできる。   The gold plating solution of the present invention is very stable because gold deposition is suppressed by 55% by weight or more of the protophilic solvent. For this reason, it is also easy to perform alloy plating by adding one or more kinds of metals. Silver and copper are known to dissolve well in this solution, but other metals can be used as long as they can be dissolved. In that case, an additive may be further used to improve the alloy plating.

本発明の金メッキ液は、実質的にシアンを含有していないので、安全性に優れ、且つ廃液処理も容易であり、環境への負荷が低い、優れた金メッキ液である。ここで「実質的にシアンを含まない」とは、シアンを金メッキの目的のために積極的に含有させないことを意味し、全く含有しないことが好ましい。例えば、本発明の金メッキ液を調製する際に、不純物としてシアンが混入した場合にも、当然、シアンの含有量は低い方が好ましく、具体的には1重量%以下、中でも0.1重量%以下、更には0.01重量%以下特に0.001重量%以下とすることが好ましい。   Since the gold plating solution of the present invention does not substantially contain cyan, it is an excellent gold plating solution that is excellent in safety, easy to dispose of waste liquid, and has a low environmental impact. Here, “substantially no cyan” means that cyan is not actively contained for the purpose of gold plating, and is preferably not contained at all. For example, when preparing the gold plating solution of the present invention, even when cyan is mixed as an impurity, it is naturally preferable that the cyan content is low, specifically, 1% by weight or less, especially 0.1% by weight. In the following, it is further preferable that the content be 0.01% by weight or less, particularly 0.001% by weight or less.

本発明の金メッキ液を調製する場合、金源としては、金合金、または単体の金あるいは金塩などが挙げられるが、メッキ液への不純物混入防止の点から単体の金またはヨウ化金などが好ましく用いられる。この中で、入手のしやすさから単体の金が望ましい。単体の金は、金メッキ液製造方法に応じて、塊、箔、板、粒、粉等、いずれの形態でも差し支えない。   When preparing the gold plating solution of the present invention, examples of the gold source include a gold alloy, a single gold or a gold salt, but a single gold or gold iodide is used from the viewpoint of preventing impurities from being mixed into the plating solution. Preferably used. Of these, a single piece of gold is desirable because of its availability. The single gold may be in any form such as lump, foil, plate, grain, powder, etc. depending on the gold plating solution manufacturing method.

本発明の金メッキ液の製造方法は、特に制限されないが、金源、金の錯イオン源、親プロトン性溶媒、水、還元剤および必要に応じて他の添加剤を混合することにより得ることができる。   The method for producing the gold plating solution of the present invention is not particularly limited, but can be obtained by mixing a gold source, a gold complex ion source, a protic solvent, water, a reducing agent, and other additives as required. it can.

本発明の金メッキ方法は、本発明の金メッキ液中に被メッキ材料を浸漬することにより行う。このとき、浸漬槽としてはどのような槽を用いても良く、攪拌、無攪拌いずれでもよい。メッキ中には、メッキ速度を上げるため、金メッキ液を50℃以上好ましくは65℃以上に加温してもよい。加温は金メッキ液からの水分蒸発を避けるため、95℃以下が好ましく、85℃以下がより好ましい。   The gold plating method of the present invention is performed by immersing the material to be plated in the gold plating solution of the present invention. At this time, any tank may be used as the immersion tank, and either stirring or non-stirring may be used. During plating, the gold plating solution may be heated to 50 ° C. or higher, preferably 65 ° C. or higher in order to increase the plating speed. In order to avoid water evaporation from the gold plating solution, the heating is preferably 95 ° C. or lower, more preferably 85 ° C. or lower.

以下に実施例及び比較例を挙げて本発明の具体的態様を説明するが、本発明はその要旨を超えない限り、以下の実施例により何ら限定されるものではない。
なお、以下において、金は三菱マテリアル(株)製の純度99.99%以上の純金を、ヨウ素は合同資源産業(株)製の純度99.5%以上品、ヨウ化カリウムは合同資源産業(株)製の純度99.5%以上品、NMPはキシダ化学(株)の高純度溶媒、塩化金(III)酸水溶液は石福金属興業(株)製品、ジエチレングリコールは三菱化学(株)製品、それ以外の試薬については和光純薬工業(株)製の試薬特級を用いて評価を実施した。
Specific examples of the present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to the following examples unless it exceeds the gist.
In the following, gold is a pure gold with a purity of 99.99% or more manufactured by Mitsubishi Materials Corporation, iodine is a product with a purity of 99.5% or more manufactured by Joint Resource Industries, Ltd., and potassium iodide is a joint resource industry ( NMP is a high-purity solvent of Kishida Chemical Co., Ltd., chloroauric (III) acid aqueous solution is a product of Ishifuku Metal Industry Co., Ltd., diethylene glycol is a product of Mitsubishi Chemical Corporation, About other reagents, evaluation was implemented using the reagent special grade made from Wako Pure Chemical Industries Ltd.

(実施例1)
金、ヨウ素、ヨウ化カリウム、N−メチルピロリドン(NMP)、および水を混合して、Au/I/KI/NMP/HO=1/1/4/75/19(重量比)からなる金メッキ液を調製したところ、濃い褐色であった。この金メッキ液に対して、添加後の含有量として2.6重量%のチオ尿素と、2重量%のアスコルビン酸を添加したところ、金メッキ液中の三ヨウ素イオンがヨウ化物イオンに還元され、無色透明となった。この液のpHは3.2であった。
この液を80℃まで加熱し、弱く攪拌しつつ、無アルカリガラス基板上にNiを約1μmの厚さにスパッタした試料を30分間浸漬したところ、Niスパッタ膜の表面にAuが析出し、無電解メッキされていた。
生成した膜量は4.53mg/cmであった。この膜重量からAu金属の密度を用いて求めた膜厚は約2.4μmであった。
(Example 1)
Mixing gold, iodine, potassium iodide, N-methylpyrrolidone (NMP), and water, from Au / I 2 / KI / NMP / H 2 O = 1/4/75/19 (weight ratio) When the gold plating solution was prepared, it was dark brown. When 2.6% by weight of thiourea and 2% by weight of ascorbic acid were added to the gold plating solution after addition, triiodine ions in the gold plating solution were reduced to iodide ions and were colorless. It became transparent. The pH of this solution was 3.2.
When this sample was heated to 80 ° C. and weakly stirred, a sample in which Ni was sputtered to a thickness of about 1 μm on a non-alkali glass substrate was immersed for 30 minutes. As a result, Au was deposited on the surface of the Ni sputtered film. It was electroplated.
The amount of film produced was 4.53 mg / cm 2 . The film thickness obtained from the film weight using the density of Au metal was about 2.4 μm.

(実施例2)
実施例1と同様にして、Au/I/KI/NMP/HO=1/1/4/70/24(重量比)からなるメッキ液を調製したところ、濃い褐色であった。このメッキ液に対して、添加後の含有量として2.6重量%のチオ尿素と、2重量%のアスコルビン酸を添加したところ、メッキ液中の三ヨウ素イオンがヨウ化物イオンに還元され、無色透明となった。
この液を80℃まで加熱し、弱く攪拌しつつ、無アルカリガラス基板上にNiを約1μmの厚さにスパッタした試料を30分間浸漬したところ、初めのうちはNiスパッタ膜の表面にAuが析出し、無電解メッキされていた。途中から膜が剥がれはじめたため、膜厚の計測はできなかったが、色は金色に変わり、Auの析出が確認された。
(Example 2)
When a plating solution consisting of Au / I 2 / KI / NMP / H 2 O = 1/1/4/70/24 (weight ratio) was prepared in the same manner as in Example 1, it was dark brown. When 2.6% by weight of thiourea and 2% by weight of ascorbic acid were added to the plating solution as a content after addition, triiodine ions in the plating solution were reduced to iodide ions, and colorless. It became transparent.
When this sample was heated to 80 ° C. and weakly stirred, a sample obtained by sputtering Ni to a thickness of about 1 μm on an alkali-free glass substrate was immersed for 30 minutes. At first, Au was deposited on the surface of the Ni sputtered film. It was deposited and electrolessly plated. Since the film began to peel off in the middle, the film thickness could not be measured, but the color changed to gold and the deposition of Au was confirmed.

(実施例3)
実施例1と同様にして、Au/I/KI/NMP/HO=1/1/4/60/34(重量比)からなるメッキ液を調製したところ、濃い褐色であった。このメッキ液に対して、添加後の含有量として2.6重量%のチオ尿素と、2重量%のアスコルビン酸を添加したところ、メッキ液中の三ヨウ素イオンがヨウ化物イオンに還元され、無色透明となった。
この液を80℃まで加熱し、弱く攪拌しつつ、無アルカリガラス基板上にNiを約1μmの厚さにスパッタした試料を30分間浸漬したところ、初めのうちはNiスパッタ膜の表面にAuが析出し、無電解メッキされていた。途中から膜が剥がれはじめたため、膜厚の計測はできなかったが、色は金色に変わり、Auの析出が確認された。
(Example 3)
When a plating solution consisting of Au / I 2 / KI / NMP / H 2 O = 1/1/4/60/34 (weight ratio) was prepared in the same manner as in Example 1, it was dark brown. When 2.6% by weight of thiourea and 2% by weight of ascorbic acid were added to the plating solution as a content after addition, triiodine ions in the plating solution were reduced to iodide ions, and colorless. It became transparent.
When this sample was heated to 80 ° C. and weakly stirred, a sample obtained by sputtering Ni to a thickness of about 1 μm on an alkali-free glass substrate was immersed for 30 minutes. At first, Au was deposited on the surface of the Ni sputtered film. It was deposited and electrolessly plated. Since the film began to peel off in the middle, the film thickness could not be measured, but the color changed to gold and the deposition of Au was confirmed.

(実施例4)
実施例1と同様にして、Au/I/KI/NMP/HO=1/1/4/75/19(重量比)からなるメッキ液を調製したところ、濃い褐色であった。このメッキ液に対して、添加後の含有量として2.6重量%のチオ尿素を添加したところ、メッキ液中の三ヨウ素イオンがヨウ化物イオンに還元され、やや薄くなった。
この液を80℃まで加熱し、弱く攪拌しつつ、無アルカリガラス基板上にNiを約1μmの厚さにスパッタした試料を30分間浸漬したところ、Niスパッタ膜の表面にAuがわずかに析出し、無電解メッキされていた。析出膜が非常に薄いため膜厚の計測はできなかったが、色は金色に変わり、Auの析出が確認された。
Example 4
When a plating solution comprising Au / I 2 / KI / NMP / H 2 O = 1/1/4/75/19 (weight ratio) was prepared in the same manner as in Example 1, it was dark brown. When 2.6% by weight of thiourea was added to the plating solution as a content after the addition, triiodine ions in the plating solution were reduced to iodide ions and became slightly thinner.
When this sample was heated to 80 ° C. and stirred gently, a sample obtained by sputtering Ni to a thickness of about 1 μm on an alkali-free glass substrate was immersed for 30 minutes. As a result, Au was slightly deposited on the surface of the Ni sputtered film. Was electrolessly plated. Since the deposited film was very thin, the film thickness could not be measured, but the color changed to gold and the deposition of Au was confirmed.

(実施例5)
実施例1と同様にして、Au/I/KI/NMP/HO=0.2/0.2/0.8/73/25.8(重量比)からなるメッキ液を調製したところ、濃い褐色であった。このメッキ液に対して、添加後の含有量として1.3重量%のアスコルビン酸を添加したところ、メッキ液中の三ヨウ素イオンがヨウ化物イオンに還元され、無色透明となった。さらに、元の液に対して、1.2重量%のサリチル酸と、0.2重量%の50重量%KOH水溶液を添加してメッキ液を調製した。
この液を80℃まで加熱し、弱く攪拌しつつ、無アルカリガラス基板上にNiを約1μmの厚さにスパッタした試料を30分間浸漬したところ、Niスパッタ膜の表面にAuがわずかに析出し、無電解メッキされていた。析出膜が非常に薄いため膜厚の計測はできなかったが、色は金色に変わり、Auの析出が確認された。
(Example 5)
In the same manner as in Example 1, a plating solution having Au / I 2 / KI / NMP / H 2 O = 0.2 / 0.2 / 0.8 / 73 / 25.8 (weight ratio) was prepared. It was dark brown. When 1.3% by weight of ascorbic acid was added to the plating solution as a content after the addition, triiodine ions in the plating solution were reduced to iodide ions and became colorless and transparent. Furthermore, 1.2 wt% salicylic acid and 0.2 wt% 50 wt% KOH aqueous solution were added to the original solution to prepare a plating solution.
When this sample was heated to 80 ° C. and stirred gently, a sample obtained by sputtering Ni to a thickness of about 1 μm on an alkali-free glass substrate was immersed for 30 minutes. As a result, Au was slightly deposited on the surface of the Ni sputtered film. Was electrolessly plated. Since the deposited film was very thin, the film thickness could not be measured, but the color changed to gold and the deposition of Au was confirmed.

(実施例6)
塩化金(III)酸水溶液(Au濃度100g/L(Auとして)、塩酸濃度60g/L)/水/NMP=11.5/13.5/75(重量比)からなるメッキ液を調製したところ、黄色透明であった。この液に対して、添加後の含有量として2.6重量%のチオ尿素を添加して、静置し、4日後に確認したところ無色透明であった。
この液を80℃まで加熱し、無アルカリガラス基板上にNiを約1μmの厚さにスパッタした試料を20分間浸漬したところ、Niスパッタ膜の表面に約1mg/cmのAuが析出し、無電解メッキされていた。このとき、膜重量とAu密度から換算した膜厚は0.5μmであった。
(Example 6)
A plating solution comprising an aqueous solution of gold chloride (III) acid (Au concentration 100 g / L (as Au), hydrochloric acid concentration 60 g / L) /water/NMP=11.5/13.5/75 (weight ratio) was prepared. Yellow transparent. To this solution, 2.6% by weight of thiourea as a content after addition was added, left to stand, and confirmed to be colorless and transparent after 4 days.
When this liquid was heated to 80 ° C. and a sample obtained by sputtering Ni to a thickness of about 1 μm on an alkali-free glass substrate was immersed for 20 minutes, about 1 mg / cm 2 of Au was deposited on the surface of the Ni sputtered film, It was electrolessly plated. At this time, the film thickness converted from the film weight and Au density was 0.5 μm.

(比較例1)
Au/I/KI/NMP/HO=1/1/4/50/44(重量比)からなるメッキ液を調製したところ、濃い褐色であった。このメッキ液に対して、添加後の含有量として2.6重量%のチオ尿素と、2重量%のアスコルビン酸を添加したところ、メッキ液中の三ヨウ素イオンがヨウ化物イオンに還元され、無色透明となったが、その時点でAuが析出して、安定な無電解メッキ液は得られなかった。
(Comparative Example 1)
When a plating solution composed of Au / I 2 / KI / NMP / H 2 O = 1/1/4/50/44 (weight ratio) was prepared, it was dark brown. When 2.6% by weight of thiourea and 2% by weight of ascorbic acid were added to the plating solution as a content after addition, triiodine ions in the plating solution were reduced to iodide ions, and colorless. Although it became transparent, Au was deposited at that time, and a stable electroless plating solution could not be obtained.

(比較例2)
塩化金(III)酸水溶液(Au濃度100g/L(Auとして)、塩酸濃度60g/L)/水/NMP=11.5/38.5/50(重量比)からなるメッキ液を調製したところ、黄色透明であった。この液に対して、添加後の含有量として2.6重量%のチオ尿素を添加して、静置し、4日後に確認したところ白い結晶が析出しており、安定なメッキ液が得られなかった。
(Comparative Example 2)
A plating solution comprising an aqueous solution of gold chloride (III) acid (Au concentration 100 g / L (as Au), hydrochloric acid concentration 60 g / L) /water/NMP=11.5/38.5/50 (weight ratio) was prepared. Yellow transparent. To this solution, 2.6% by weight of thiourea was added as a content after addition, left to stand, and after 4 days, white crystals were precipitated, and a stable plating solution was obtained. There wasn't.

(比較例3)
塩化金(III)酸水溶液(Au濃度100g/L(Auとして)、塩酸濃度60g/L)/水=11.5/88.5(重量比)からなるメッキ液を調製したところ、黄色透明であった。この液に対して、添加後の含有量として2.6重量%のチオ尿素を添加して、静置し、4日後に確認したところ白い結晶が析出しており、安定なメッキ液が得られなかった。
(Comparative Example 3)
When a plating solution comprising a gold (III) chloride (III) acid aqueous solution (Au concentration 100 g / L (as Au), hydrochloric acid concentration 60 g / L) /water=11.5/88.5 (weight ratio) was prepared, it was yellow and transparent. there were. To this solution, 2.6% by weight of thiourea was added as a content after addition, left to stand, and after 4 days, white crystals were precipitated, and a stable plating solution was obtained. There wasn't.

Claims (10)

金錯イオン、水、親プロトン性溶媒および還元剤を含有してなり、親プロトン性溶媒の含有量が55〜90重量%であることを特徴とする金メッキ液。   A gold plating solution comprising a gold complex ion, water, a protic solvent and a reducing agent, wherein the content of the protic solvent is 55 to 90% by weight. 該親プロトン性溶媒が、非プロトン性極性溶媒である請求項1に記載の金メッキ液。   The gold plating solution according to claim 1, wherein the protic solvent is an aprotic polar solvent. 該親プロトン性溶媒が、ラクタム構造を有する請求項1又は2に記載の金メッキ液。   The gold plating solution according to claim 1 or 2, wherein the protic solvent has a lactam structure. 該親プロトン性溶媒が、N−アルキルピロリドンである請求項3に記載の金メッキ液。   The gold plating solution according to claim 3, wherein the protic solvent is N-alkylpyrrolidone. 該親プロトン性溶媒100重量%に対して水を10〜50重量%含有する請求項1乃至4のいずれか1項に記載の金メッキ液。   The gold plating solution according to any one of claims 1 to 4, comprising 10 to 50% by weight of water with respect to 100% by weight of the protophilic solvent. シアンを実質的に含まない請求項1乃至5のいずれか1項に記載の金メッキ液。   The gold plating solution according to any one of claims 1 to 5, which is substantially free of cyan. 三ヨウ素イオンを実質的に含まない請求項1乃至6のいずれか1項に記載の金メッキ液。   The gold plating solution according to any one of claims 1 to 6, substantially free of triiodine ions. 還元剤を0.01〜10重量%含有する請求項1乃至7のいずれか1項に記載の金メッキ液。   The gold plating solution according to any one of claims 1 to 7, comprising 0.01 to 10% by weight of a reducing agent. 還元剤もしくは錯化剤としてチオ尿素を含有する請求項1乃至8のいずれか1項に記載の金メッキ液。   The gold plating solution according to any one of claims 1 to 8, which contains thiourea as a reducing agent or a complexing agent. 請求項1乃至9のいずれか1項に記載の金メッキ液を用いてメッキを行うことを特徴とする金メッキ方法。   A gold plating method, wherein plating is performed using the gold plating solution according to claim 1.
JP2007009269A 2007-01-18 2007-01-18 Gold plating liquid and gold plating method Pending JP2008174796A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014041107A (en) * 2012-08-24 2014-03-06 Greenchem Inc Electrode substrate for sensor, and sensor using the same
JP2021511438A (en) * 2018-01-26 2021-05-06 アトテック ドイチェランド ゲーエムベーハー Electroless gold plating bath

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58133366A (en) * 1982-02-01 1983-08-09 Hitachi Chem Co Ltd Electroless copper plating solution
JPH06280039A (en) * 1993-03-26 1994-10-04 C Uyemura & Co Ltd Electroless gold plating bath
JP2004360006A (en) * 2003-06-04 2004-12-24 Mitsubishi Chemicals Corp Gold plating liquid, and gold plating method

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58133366A (en) * 1982-02-01 1983-08-09 Hitachi Chem Co Ltd Electroless copper plating solution
JPH06280039A (en) * 1993-03-26 1994-10-04 C Uyemura & Co Ltd Electroless gold plating bath
JP2004360006A (en) * 2003-06-04 2004-12-24 Mitsubishi Chemicals Corp Gold plating liquid, and gold plating method

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014041107A (en) * 2012-08-24 2014-03-06 Greenchem Inc Electrode substrate for sensor, and sensor using the same
JP2021511438A (en) * 2018-01-26 2021-05-06 アトテック ドイチェランド ゲーエムベーハー Electroless gold plating bath
JP7297771B2 (en) 2018-01-26 2023-06-26 アトテック ドイチェランド ゲーエムベーハー ウント コ カーゲー Electroless gold plating bath

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