JP2000212761A - Electroless plating method and electroless plating bath - Google Patents
Electroless plating method and electroless plating bathInfo
- Publication number
- JP2000212761A JP2000212761A JP11011959A JP1195999A JP2000212761A JP 2000212761 A JP2000212761 A JP 2000212761A JP 11011959 A JP11011959 A JP 11011959A JP 1195999 A JP1195999 A JP 1195999A JP 2000212761 A JP2000212761 A JP 2000212761A
- Authority
- JP
- Japan
- Prior art keywords
- electroless plating
- plating bath
- amount
- plating
- reducing agent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】この発明は、無電解めっき浴
に関するもので、特に、めっき浴の成分を補充せずに、
めっき開始時に必要な量だけを添加することによって、
一度のめっき処理ごとにめっき浴の成分を使い切る、無
電解銅めっき浴に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroless plating bath, in particular, without replenishing the components of the plating bath.
By adding only the necessary amount at the start of plating,
The present invention relates to an electroless copper plating bath in which the components of a plating bath are used up every time a plating process is performed.
【０００２】[0002]
【従来の技術】工業的に用いられている無電解めっき浴
は、一般に、水溶液中に金属イオンと還元剤を含有し、
さらに、金属イオンの沈殿を防止するための錯化剤、お
よび、水溶液をアルカリ性に保つためのｐＨ調整剤が添
加されているものが多く用いられている。具体的には、
金属イオンの供給剤としては、例えば硫酸塩のようなめ
っき液に対する溶解度の高い金属塩が用いられる。ま
た、還元剤としてはホルムアルデヒドが、錯化剤として
はＥＤＴＡが多く用いられる。さらに、ｐＨ調整剤とし
ては、例えば水酸化ナトリウム等のアルカリ金属水酸化
物が添加される場合も多い。これらの各成分からなるめ
っき浴を用いた無電解めっきにおいては、めっき浴中の
各成分に不足が生じないように、めっき反応の進行に伴
い消費される各成分を補充しながらめっきを行うのが一
般的である。2. Description of the Related Art Generally, an electroless plating bath used industrially contains a metal ion and a reducing agent in an aqueous solution,
Further, those containing a complexing agent for preventing precipitation of metal ions and a pH adjuster for keeping an aqueous solution alkaline have been used in many cases. In particular,
As a metal ion supply agent, a metal salt having high solubility in a plating solution such as a sulfate is used. Formaldehyde is often used as a reducing agent, and EDTA is often used as a complexing agent. Furthermore, as a pH adjuster, for example, an alkali metal hydroxide such as sodium hydroxide is often added. In electroless plating using a plating bath composed of these components, plating is performed while replenishing each component consumed with the progress of the plating reaction so that each component in the plating bath does not become insufficient. Is common.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、上述の
無電解めっき方法には次のような問題がある。すなわ
ち、この無電解めっき方法においては、金属イオンを還
元することによって、被めっき物上にめっき膜を生成す
るが、この金属イオンの還元にあたり大量の還元剤や水
酸化物が消費され、大量の反応生成物が生成する。たと
えば、金属イオン供給剤として硫酸塩、還元剤としてホ
ルムアルデヒド、ｐＨ調整剤としてＮａＯＨを使用する
場合、この還元反応生成物として、硫酸ナトリウムやギ
酸等が生成する。上述のように、この無電解めっき方法
では、めっき浴中の消費された成分を補充しながらめっ
き処理を行うため、めっき回数が多くなるにしたがっ
て、このような還元反応生成物がめっき浴中に増加、蓄
積し、めっき膜へ不純物として析出するなど、めっき膜
質に影響を与えることとなる。However, the above-mentioned electroless plating method has the following problems. That is, in the electroless plating method, a metal ion is reduced to form a plating film on the object to be plated. However, a large amount of a reducing agent or hydroxide is consumed in the reduction of the metal ion, and a large amount of the metal ion is consumed. A reaction product forms. For example, when a sulfate is used as a metal ion supply agent, formaldehyde is used as a reducing agent, and NaOH is used as a pH adjuster, sodium sulfate, formic acid, and the like are generated as the reduction reaction products. As described above, in this electroless plating method, since the plating treatment is performed while replenishing the consumed components in the plating bath, as the number of plating increases, such a reduction reaction product is contained in the plating bath. It increases, accumulates and precipitates as an impurity on the plating film, thereby affecting the quality of the plating film.
【０００４】また、還元反応を促進させるために、被め
っき物にあらかじめ活性化処理を施すこともあるが、こ
の場合、めっき処理の途中で、余分な活性化触媒が被め
っき物から剥離し、その剥離した活性化触媒上へめっき
皮膜が析出することがしばしばある。その結果、めっき
浴中に不純物が増加するとともに、めっきの析出効率が
低下する。In order to promote the reduction reaction, an object to be plated may be subjected to an activation treatment in advance. In this case, during the plating treatment, an extra activation catalyst is peeled off from the object to be plated. A plating film is often deposited on the separated activated catalyst. As a result, impurities increase in the plating bath, and the plating deposition efficiency decreases.
【０００５】さらに、無電解めっきの中でも特に無電解
銅めっきは、無電解ニッケルめっき等と比較すると、め
っき浴の安定性が悪い。すなわち、無電解銅めっきは銅
イオンが直接Ｃｕに還元される反応（通常反応）を利用
するが、この通常反応だけでなく副反応として不均化反
応も起こる。この場合の不均化反応とは、めっき浴中の
銅イオンがいったんＣｕ2Ｏに還元され、その後にＣｕ
に還元される反応のことであるが、この不均化反応によ
って生成したＣｕは被めっき物上に析出するのではな
く、めっき浴中に銅粉として析出することになる。銅は
触媒性を有するため、該銅粉上にはさらに銅が析出す
る。このようにして、めっき浴中に銅粉が蓄積し、めっ
き浴中に不純物が増加するとともに、めっきの析出効率
が低下する。Further, among electroless plating, especially electroless copper plating has poor stability of a plating bath as compared with electroless nickel plating or the like. That is, electroless copper plating utilizes a reaction (normal reaction) in which copper ions are directly reduced to Cu, but not only this normal reaction but also a disproportionation reaction occurs as a side reaction. The disproportionation reaction in this case means that the copper ions in the plating bath are once reduced to Cu 2 O,
The Cu produced by the disproportionation reaction does not precipitate on the object to be plated, but precipitates as copper powder in the plating bath. Since copper has catalytic properties, copper is further precipitated on the copper powder. In this manner, copper powder accumulates in the plating bath, impurities increase in the plating bath, and the plating deposition efficiency decreases.
【０００６】また、めっき終了後のめっき浴は、利用で
きる成分を回収し再利用している。しかし、めっき浴中
に銅イオンが多く残留している場合、錯化剤の回収効率
は低下するため、銅イオンを高ｐＨで還元、除去してか
ら、錯化剤を回収する必要がある。[0006] Further, in the plating bath after completion of the plating, usable components are recovered and reused. However, when a large amount of copper ions remains in the plating bath, the recovery efficiency of the complexing agent is reduced. Therefore, it is necessary to reduce and remove the copper ions at a high pH before recovering the complexing agent.
【０００７】そこで、本発明の目的は、めっき処理時に
還元反応生成物がめっき浴中に蓄積せず、活性化触媒の
剥離や不均化反応等によって生じた銅粉がめっき浴中に
蓄積しにくく、めっき終了後の成分の回収が容易な無電
解めっき方法および無電解めっき浴を提供することにあ
る。[0007] Therefore, an object of the present invention is to prevent the reduction reaction product from accumulating in the plating bath during the plating treatment, and to accumulate in the plating bath copper powder generated by the separation of the activation catalyst or the disproportionation reaction. An object of the present invention is to provide an electroless plating method and an electroless plating bath which are difficult to recover components after plating.
【０００８】[0008]
【課題を解決するための手段】本発明は、無電解めっき
方法、および、無電解めっき浴に向けられるものであっ
て、上述した技術的課題を解決するため、次のような構
成を備えることを特徴としている。SUMMARY OF THE INVENTION The present invention is directed to an electroless plating method and an electroless plating bath. To solve the above-mentioned technical problems, the present invention has the following arrangement. It is characterized by.
【０００９】本発明は、めっき浴の各成分を補充せず
に、めっき開始時に必要な量のみを添加することによっ
て、一度のめっき処理ごとにめっき浴の各成分を使い切
ること、および、不均化反応の進行をできる限り抑制す
るような濃度に各成分の添加量を調整することによって
めっきの析出効率を上げることを特徴とする。According to the present invention, each component of a plating bath is used up once per plating process by adding only a necessary amount at the start of plating without replenishing each component of the plating bath. It is characterized in that the deposition efficiency of plating is increased by adjusting the addition amount of each component to a concentration that suppresses the progress of the chemical reaction as much as possible.
【００１０】すなわち、本発明は、金属イオン、錯化
剤、還元剤、ｐＨ調整剤を含む無電解めっき浴を用意す
る工程と、無電解めっき浴を用いて無電解めっきを行う
工程とを有する無電解めっき方法において、無電解めっ
き浴を用意する工程における無電解めっき浴の還元剤の
含有量を、無電解めっきを行う工程でのめっき終了時に
還元剤が消費し尽くされる量としたことを特徴とする。
ここで、めっき終了時に還元剤が消費し尽くされる量と
は、還元剤の蒸発量と自己分解相当量を含み、かつ、十
分な還元反応が起こり、過剰な不均化反応を防ぐような
量を指すとする。That is, the present invention comprises a step of preparing an electroless plating bath containing a metal ion, a complexing agent, a reducing agent, and a pH adjuster, and a step of performing electroless plating using the electroless plating bath. In the electroless plating method, the content of the reducing agent in the electroless plating bath in the step of preparing the electroless plating bath is set to an amount such that the reducing agent is consumed at the end of plating in the step of performing the electroless plating. Features.
Here, the amount of the reducing agent consumed at the end of plating includes the amount of evaporation of the reducing agent and the amount equivalent to self-decomposition, and an amount such that a sufficient reduction reaction occurs and an excessive disproportionation reaction is prevented. Let's say
【００１１】このように、還元剤をめっき開始時に必要
な量だけ添加し、一度のめっき処理ごとにめっき浴を交
換することによって、還元剤を補充しながら繰り返しめ
っき処理を行う従来技術のように、還元反応の生成物が
めっき浴中に大量に蓄積するのを防ぐことができる。ま
た、還元剤を必要な量だけ添加することによって、過剰
な不均化反応の進行を抑制し、めっき浴中に金属粉が析
出することを防ぐことができる。[0011] As described above, by adding a necessary amount of a reducing agent at the start of plating and exchanging a plating bath for each plating process, the plating process is repeated while replenishing the reducing agent. In addition, it is possible to prevent a large amount of products of the reduction reaction from accumulating in the plating bath. Further, by adding a necessary amount of the reducing agent, it is possible to suppress the progress of the excessive disproportionation reaction and to prevent the metal powder from being precipitated in the plating bath.
【００１２】また、本発明は、金属イオン、錯化剤、還
元剤、ｐＨ調整剤を含む無電解めっき浴を用意する工程
と、無電解めっき浴を用いて無電解めっきを行う工程と
を有する無電解めっき方法において、無電解めっき浴を
用意する工程における無電解めっき浴の金属イオンの含
有量を、無電解めっきを行う工程でのめっき終了時に金
属イオンが被めっき物表面に析出し尽くす量としたこと
を特徴とする。ここで、金属イオンが被めっき物表面に
析出し尽くす量とは、十分なめっき膜の析出を得ること
ができるとともに、過剰な不均化反応の進行を抑制する
ことができるような量をいう。Further, the present invention has a step of preparing an electroless plating bath containing a metal ion, a complexing agent, a reducing agent, and a pH adjuster, and a step of performing electroless plating using the electroless plating bath. In the electroless plating method, the content of metal ions in the electroless plating bath in the step of preparing the electroless plating bath is determined by the amount by which metal ions are completely deposited on the surface of the object to be plated at the end of plating in the step of performing the electroless plating. It is characterized by having. Here, the amount by which metal ions are completely deposited on the surface of the object to be plated refers to an amount capable of obtaining a sufficient plating film deposition and suppressing excessive disproportionation progress. .
【００１３】このように、金属イオンをめっき開始時に
必要な量だけ添加し、一度のめっき処理ごとにめっき浴
を交換することによって、金属イオンを補充しながら繰
り返しめっき処理を行う従来技術のように、還元反応の
生成物がめっき浴中に大量に蓄積するのを防ぐことがで
きる。また、金属イオンを必要な量だけ添加することに
よって、十分なめっき膜の析出を得るとともに、過剰な
不均化反応の進行を抑制し、めっき浴中に金属粉が析出
するのを防ぐことができる。As described above, by adding a required amount of metal ions at the start of plating and replacing the plating bath with each plating process, the plating process is repeated while replenishing the metal ions. In addition, it is possible to prevent a large amount of products of the reduction reaction from accumulating in the plating bath. In addition, by adding a required amount of metal ions, it is possible to obtain sufficient plating film deposition, to suppress the progress of the excessive disproportionation reaction, and to prevent metal powder from being deposited in the plating bath. it can.
【００１４】また、本発明では、金属イオン、錯化剤、
還元剤、ｐＨ調整剤を含む無電解めっき浴を用意する工
程と、無電解めっき浴を用いて無電解めっきを行う工程
とを有する無電解めっき方法において、無電解めっき浴
を用意する工程における無電解めっき浴の還元剤の含有
量を、無電解めっきを行う工程でのめっき終了時に還元
剤が消費し尽くされる量とし、無電解めっき浴を用意す
る工程における無電解めっき浴の金属イオンの含有量
を、無電解めっきを行う工程でのめっき終了時に金属イ
オンが被めっき物表面に析出し尽くす量としてもよい。Further, in the present invention, a metal ion, a complexing agent,
In an electroless plating method having a step of preparing an electroless plating bath containing a reducing agent and a pH adjuster, and a step of performing electroless plating using the electroless plating bath, the process of preparing an electroless plating bath is not included. The content of the reducing agent in the electrolytic plating bath is set to an amount by which the reducing agent is consumed at the end of plating in the step of performing electroless plating, and the content of metal ions in the electroless plating bath in the step of preparing the electroless plating bath The amount may be an amount at which metal ions are completely deposited on the surface of the object to be plated at the end of plating in the step of performing electroless plating.
【００１５】金属イオンとしては例えば銅イオンを、前
記還元剤としては例えばホルムアルデヒドを使用するこ
とができる。また、前記錯化剤としては例えばＥＤＴＡ
を、前記ｐＨ調整剤としては例えばＮａＯＨを使用する
ことができる。As the metal ion, for example, copper ion can be used, and as the reducing agent, for example, formaldehyde can be used. Further, as the complexing agent, for example, EDTA
For example, NaOH can be used as the pH adjuster.
【００１６】金属イオンとして銅イオンを添加する場
合、銅イオンの添加量は、０．０６〜０．１２ｍｏｌ／
ｌとすることが好ましい。銅イオンの添加量がこの範囲
より少なければ、十分なめっき膜の析出が得られず、多
い場合は、被めっき物上への金属の析出が促進され、形
成されるめっき膜の表面が粗くなるためである。When copper ions are added as metal ions, the amount of copper ions added is from 0.06 to 0.12 mol /
It is preferably 1. If the addition amount of the copper ion is less than this range, sufficient deposition of the plating film cannot be obtained, and if it is large, the deposition of the metal on the object to be plated is promoted, and the surface of the plating film to be formed becomes rough. That's why.
【００１７】また、還元剤の添加量は、含有する金属イ
オンを還元するのに必要な理論量の１．２〜２．０倍と
することが好ましい。還元剤の添加量がこの範囲よりも
少ない場合は、還元反応が十分に起こらず、十分なめっ
き膜の析出が得にくい。一方、還元剤の添加量がこの範
囲よりも多い場合は、不均化反応の進行を促進し、めっ
き浴中に金属粉が多く析出することとなるからである。The amount of the reducing agent to be added is preferably 1.2 to 2.0 times the theoretical amount necessary for reducing the contained metal ions. If the amount of the reducing agent is less than this range, the reduction reaction does not occur sufficiently, and it is difficult to obtain a sufficient plating film. On the other hand, when the amount of the reducing agent added is larger than this range, the progress of the disproportionation reaction is promoted, and a large amount of metal powder is precipitated in the plating bath.
【００１８】また、錯化剤の添加量については、含有す
る金属イオンを錯化するのに必要な理論量の０．６〜
０．９倍とすることが好ましい。錯化剤の添加量が、こ
の範囲よりも少ない場合は、金属がイオンとして十分に
めっき浴中に保持されず析出し、多い場合は、金属の析
出が抑えられ十分な膜厚のめっき膜が得られないためで
ある。The amount of the complexing agent to be added is from 0.6 to the theoretical amount required to complex the contained metal ions.
It is preferably 0.9 times. If the amount of the complexing agent is less than this range, the metal is not sufficiently retained as ions in the plating bath and precipitates.If the amount is large, the deposition of the metal is suppressed and a plating film having a sufficient thickness is obtained. This is because they cannot be obtained.
【００１９】また、めっき浴の温度は４０℃〜６０℃程
度が適当であり、特に４５〜５５℃が好ましい。めっき
浴の温度がこの範囲よりも低い場合は、還元反応の速度
が遅く、十分なめっき膜の析出が得られない。一方、こ
の範囲よりも高い場合は、還元反応だけでなく不均化反
応も促進されるため、めっき浴中に金属粉が析出しやす
くなる。The temperature of the plating bath is suitably about 40 ° C. to 60 ° C., and particularly preferably 45 ° C. to 55 ° C. If the temperature of the plating bath is lower than this range, the speed of the reduction reaction is low, and a sufficient deposition of a plating film cannot be obtained. On the other hand, when it is higher than this range, not only the reduction reaction but also the disproportionation reaction are promoted, so that the metal powder tends to precipitate in the plating bath.
【００２０】さらに、無電解めっき浴に、３７．５〜１
３１ｌ／ｈのエアーを通気しながら無電解めっきを行う
のが望ましい。不均化反応において、めっき浴中の銅イ
オンはいったんＣｕ2Ｏに還元されるが、めっき浴にエ
アーを通気することによって供給された酸素を用いて、
Ｃｕ2Ｏを再び銅イオンに酸化し、不均化反応の進行を
抑制することができる。しかし、エアーの通気量がこの
範囲よりも少ない場合は、Ｃｕ2Ｏを銅イオンに酸化す
るのに十分な酸素が供給されず、不均化反応を抑制でき
ない。一方、エアーの通気量がこの範囲よりも多い場合
は、析出したＣｕが酸化され、めっき外観が黒くなると
ともに、析出したＣｕが再溶解し、めっき膜厚が低下す
る。Further, 37.5 to 1
It is desirable to perform electroless plating while ventilating 31 l / h of air. In the disproportionation reaction, the copper ions in the plating bath are once reduced to Cu 2 O, but using oxygen supplied by blowing air through the plating bath,
Cu 2 O is oxidized again to copper ions, and the progress of the disproportionation reaction can be suppressed. However, if the air flow rate is smaller than this range, oxygen sufficient to oxidize Cu 2 O to copper ions is not supplied, and the disproportionation reaction cannot be suppressed. On the other hand, when the air flow rate is larger than this range, the deposited Cu is oxidized, the plating appearance becomes black, and the deposited Cu is redissolved, and the plating film thickness is reduced.
【００２１】[0021]
【発明の実施の形態】本発明の一実施形態を説明する。
まず、同軸形状の誘電体共振器用セラミック素体を用意
する。セラミック素体は、例えば、Ｔｉ−Ｂａ−Ｐｂ−
Ｎｄ系の誘電体からなる。DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described.
First, a coaxial ceramic body for a dielectric resonator is prepared. The ceramic body is, for example, Ti-Ba-Pb-
It is made of an Nd-based dielectric.
【００２２】次いで、複数のセラミック素体をバレル内
に装填し、バレルを回転させながら以下に述べる一連の
無電解めっきの前処理を行う。すなわち、まず、セラミ
ック素体の表面を脱脂処理する。この脱脂処理にあたっ
ては、例えば、４０〜５０℃のケイ酸塩水溶液中に、セ
ラミック素体を１０分間程度浸漬する。続いて、セラミ
ック素体の表面を化学的にエッチング処理するため、例
えば、３０〜４０℃のホウフッ化水素酸水溶液中に、セ
ラミック素体を１０分間程度浸漬する。次に、セラミッ
ク素体の表面を感受性化処理するため、例えば、２０〜
３０℃の塩化第１錫水溶液中に、セラミック素体を１０
分間程度浸漬する。続いて、セラミック素体の表面を活
性化処理するため、例えば、２０〜３０℃の塩化パラジ
ウム水溶液中に、セラミック素体を１０分間程度浸漬す
る。以上で、無電解めっきの前処理が終了する。Next, a plurality of ceramic bodies are loaded in a barrel, and a series of pretreatments for electroless plating described below are performed while rotating the barrel. That is, first, the surface of the ceramic body is degreased. In this degreasing treatment, for example, the ceramic body is immersed in a silicate aqueous solution at 40 to 50 ° C. for about 10 minutes. Subsequently, in order to chemically etch the surface of the ceramic body, for example, the ceramic body is immersed in an aqueous solution of borofluoric acid at 30 to 40 ° C. for about 10 minutes. Next, in order to sensitize the surface of the ceramic body, for example, 20 to
In a stannous chloride aqueous solution at 30 ° C., 10
Soak for about a minute. Subsequently, in order to activate the surface of the ceramic body, the ceramic body is immersed in, for example, an aqueous solution of palladium chloride at 20 to 30 ° C. for about 10 minutes. Thus, the pretreatment of the electroless plating is completed.
【００２３】次いで、セラミック素体をバレル内に装填
したままの状態で、セラミック素体の表面に無電解銅め
っきを施す。この無電解銅めっき処理にあたっては、硫
酸銅−ＥＤＴＡ−ホルマリン（ホルムアルデヒドの水溶
液）−ＮａＯＨ組成のめっき浴中に、エアーを供給しな
がらセラミック素体を浸漬する。次いで、セラミック素
体を水洗処理し、セラミック素体の表面に付着した余剰
のめっき成分を除去するとともに、無電解めっき反応を
停止する。具体的には、例えば、２０〜３０℃のイオン
交換水中にセラミック素体を１５分間程度浸漬する。以
上で、無電解めっき処理が終了し、セラミック素体表面
に銅電極が形成される。これらの無電解めっき処理の
間、バレルは４ｒｐｍの速度で回転させた。Next, the surface of the ceramic body is subjected to electroless copper plating with the ceramic body still loaded in the barrel. In this electroless copper plating treatment, the ceramic body is immersed in a plating bath having a composition of copper sulfate-EDTA-formalin (aqueous solution of formaldehyde) -NaOH while supplying air. Next, the ceramic body is washed with water to remove excess plating components adhering to the surface of the ceramic body and stop the electroless plating reaction. Specifically, for example, the ceramic body is immersed in ion-exchanged water at 20 to 30 ° C. for about 15 minutes. Thus, the electroless plating process is completed, and a copper electrode is formed on the surface of the ceramic body. During these electroless plating processes, the barrel was rotated at a speed of 4 rpm.
【００２４】次いで、上述の水洗水を除去するため、乾
燥工程に付す。この乾燥工程では、例えば、７０〜８０
℃の温風を２０分間程度付与する。以上の工程を経て、
セラミック素体の表面に銅電極を有する誘電体共振器が
得られる。Next, a drying step is performed to remove the above-mentioned washing water. In this drying step, for example, 70 to 80
C. Warm air is applied for about 20 minutes. Through the above steps,
A dielectric resonator having a copper electrode on the surface of the ceramic body is obtained.
【００２５】[0025]
【実験例１】上述の実施形態に従いながら、以下の表１
に示すような試料を作製した。これらの試料は、無電解
めっき処理におけるめっき浴に添加したホルマリンの量
がそれぞれ異なるものである。また、この際、めっき浴
の温度は５０℃、めっき時間は６０分間、供給エアー量
は７．５ｌ／ｍｉｎ、めっき浴の液量は３．２ｌとし、
めっき浴に添加した硫酸銅の量は０．１０ｍｏｌ／ｌ、
ＥＤＴＡの量は０．０８ｍｏｌ／ｌとした。EXPERIMENTAL EXAMPLE 1 The following Table 1 was used in accordance with the above-described embodiment.
Samples as shown in Table 1 were prepared. These samples differ in the amount of formalin added to the plating bath in the electroless plating process. At this time, the temperature of the plating bath was 50 ° C., the plating time was 60 minutes, the amount of supplied air was 7.5 l / min, and the liquid volume of the plating bath was 3.2 l.
The amount of copper sulfate added to the plating bath was 0.10 mol / l,
The amount of EDTA was 0.08 mol / l.
【００２６】[0026]
【表１】 [Table 1]
【００２７】表１に示すように、還元剤であるホルマリ
ン（ホルムアルデヒド）の添加量が、銅イオンを還元す
るのに必要な理論量の１．２倍よりも少ない場合は、銅
イオンを十分に還元することができず、十分な膜厚の銅
めっきの析出が得られない。一方、２．１倍よりも多い
場合は、不均化反応が進み、めっき浴中に銅粉が析出す
る。したがって、ホルムアルデヒドの添加量は、銅イオ
ンを還元するのに必要な理論量の１．２〜２．１倍が適
当である。理論量よりも多く必要なのは、ホルムアルデ
ヒドは揮発性が高く、分解し易いため、理論量に加えて
蒸発量と自己分解相当量が必要なためであると考えられ
る。As shown in Table 1, when the addition amount of formalin (formaldehyde) as a reducing agent is less than 1.2 times the theoretical amount required to reduce copper ions, copper ions can be sufficiently reduced. It cannot be reduced, and copper plating of sufficient thickness cannot be deposited. On the other hand, if it is more than 2.1 times, the disproportionation reaction proceeds, and copper powder is precipitated in the plating bath. Therefore, the amount of formaldehyde to be added is suitably 1.2 to 2.1 times the theoretical amount required to reduce copper ions. It is considered that the reason why the amount is required to be larger than the stoichiometric amount is that formaldehyde has a high volatility and is easily decomposed, and thus, in addition to the stoichiometric amount, an evaporation amount and a considerable amount of self-decomposition are required.
【００２８】[0028]
【実験例２】上述の実施形態に従いながら、以下の表２
に示すような試料を作製した。これらの試料は、無電解
めっき処理におけるめっき浴に添加した硫酸銅の量がそ
れぞれ異なるものである。また、この際、めっき浴の温
度は５０℃、めっき時間は６０分間、供給エアー量は
７．５ｌ／ｍｉｎ、めっき浴の液量は３．２ｌとし、め
っき浴に添加したホルマリン（ホルムアルデヒド）の量
は添加された銅イオンを還元するのに必要な理論量の
１．２倍、 ＥＤＴＡの量は添加された銅イオンを錯化
するのに必要な理論量の０．８倍とした。[Experimental Example 2] The following Table 2 was used in accordance with the above-described embodiment.
Samples as shown in Table 1 were prepared. These samples differ in the amount of copper sulfate added to the plating bath in the electroless plating process. At this time, the temperature of the plating bath was 50 ° C., the plating time was 60 minutes, the supply air amount was 7.5 l / min, the liquid volume of the plating bath was 3.2 liters, and the amount of formalin (formaldehyde) added to the plating bath was The amount was 1.2 times the theoretical amount required to reduce the added copper ions, and the amount of EDTA was 0.8 times the theoretical amount required to complex the added copper ions.
【００２９】[0029]
【表２】 [Table 2]
【００３０】表２に示すように、銅イオンの添加量が、
０．０６ｍｏｌ／ｌよりも少ない場合は、十分な膜厚の
銅めっきの析出が得られない。一方、０．１２ｍｏｌ／
ｌよりも多い場合は、被めっき物上への金属の析出が促
進され、形成されるめっき膜の表面が粗くなる。また、
不均化反応が進むため、めっき浴中に銅粉が析出する。
したがって、めっき浴へ添加する銅イオンは、０．０６
〜０．１２ｍｏｌ／ｌが適当である。As shown in Table 2, the amount of copper ion added was
If the amount is less than 0.06 mol / l, deposition of copper plating having a sufficient film thickness cannot be obtained. On the other hand, 0.12 mol /
If it is more than 1, the deposition of metal on the object to be plated is promoted, and the surface of the formed plating film becomes rough. Also,
Since the disproportionation reaction proceeds, copper powder precipitates in the plating bath.
Therefore, the copper ion added to the plating bath is 0.06
０．１0.12 mol / l is appropriate.
【００３１】[0031]
【実験例３】上述の実施形態に従いながら、以下の表３
に示すような試料を作製した。これらの試料は、無電解
めっき処理におけるめっき浴に添加したＥＤＴＡの量が
それぞれ異なるものである。また、この際、めっき浴の
温度は５０℃、めっき時間は６０分間、供給エアー量は
７．５ｌ／ｍｉｎ、めっき浴の液量は３．２ｌとし、め
っき浴に添加した硫酸銅の量は０．１０ｍｏｌ／ｌ、ホ
ルマリン（ホルムアルデヒド）の量は０．２４ｍｏｌ／
ｌとした。[Experimental Example 3] The following Table 3 was used in accordance with the above-described embodiment.
Samples as shown in Table 1 were prepared. These samples differ in the amount of EDTA added to the plating bath in the electroless plating process. At this time, the temperature of the plating bath was 50 ° C., the plating time was 60 minutes, the supply air amount was 7.5 l / min, the liquid volume of the plating bath was 3.2 liters, and the amount of copper sulfate added to the plating bath was 0.10 mol / l, the amount of formalin (formaldehyde) is 0.24 mol / l
l.
【００３２】[0032]
【表３】 [Table 3]
【００３３】表３に示すように、ＥＤＴＡの添加量が、
添加された銅イオンを錯化するのに必要な理論量の０．
６倍よりも少ない場合は、銅をめっき浴中にイオンとし
て十分に捕らえておくことができず、銅粉が析出する。
一方、０．９倍よりも多い場合は、銅イオンの還元が抑
えられ、十分な膜厚の銅めっきの析出が得られない。し
たがって、めっき浴へ添加するＥＤＴＡは、添加された
銅イオンを錯化するのに必要な理論量の０．６〜０．９
倍が適当である。As shown in Table 3, the amount of EDTA added was
The theoretical stoichiometric amount of 0,1 required to complex the added copper ions.
If the amount is less than 6 times, copper cannot be sufficiently captured as ions in the plating bath, and copper powder will precipitate.
On the other hand, when the ratio is more than 0.9 times, reduction of copper ions is suppressed, and deposition of copper plating having a sufficient film thickness cannot be obtained. Therefore, EDTA added to the plating bath is 0.6 to 0.9 of the theoretical amount required to complex the added copper ions.
Double is appropriate.
【００３４】[0034]
【実験例４】上述の実施形態に従いながら、以下の表４
に示すような試料を作製した。これらの試料は、無電解
めっき処理におけるめっき浴の温度がそれぞれ異なるも
のである。また、この際、めっき時間は６０分間、供給
エアー量は７．５ｌ／ｍｉｎ、めっき浴の液量は３．２
ｌとし、めっき浴に添加した硫酸銅の量は０．１０ｍｏ
ｌ／ｌ、ホルマリン（ホルムアルデヒド）の量は０．２
４ｍｏｌ／ｌ、ＥＤＴＡの量は０．０８ｍｏｌ／ｌとし
た。[Experimental Example 4] According to the above embodiment, the following Table 4 was used.
Samples as shown in Table 1 were prepared. These samples have different plating bath temperatures in the electroless plating process. At this time, the plating time was 60 minutes, the supply air amount was 7.5 l / min, and the plating bath liquid amount was 3.2.
1 and the amount of copper sulfate added to the plating bath is 0.10 mo
l / l, the amount of formalin (formaldehyde) is 0.2
4 mol / l and the amount of EDTA was 0.08 mol / l.
【００３５】[0035]
【表４】 [Table 4]
【００３６】表４において、析出効率とは、｛（Ｃｕ添
加量−めっき終了時の浴中のＣｕ残量／Ｃｕ添加量）×
１００｝とする。表４に示すように、これらの温度領域
においては、比較的高い析出効率が得られている。しか
し、めっき浴の温度が４５℃よりも低い場合は、還元反
応の速度が遅いため、十分な膜厚の銅めっきの析出が得
られない。一方、５５℃よりも多い場合は、還元反応だ
けでなく不均化反応も促進されるため、めっき浴中に銅
粉が析出する。したがって、めっき浴の温度は、４５〜
５５℃が適当であるといえる。In Table 4, the deposition efficiency is represented by ｛(Cu addition amount−Cu remaining amount in bath at the end of plating / Cu addition amount) ×
It shall be 100 °. As shown in Table 4, in these temperature ranges, a relatively high deposition efficiency is obtained. However, when the temperature of the plating bath is lower than 45 ° C., the rate of the reduction reaction is low, and thus a copper plating of a sufficient thickness cannot be deposited. On the other hand, when the temperature is higher than 55 ° C., not only the reduction reaction but also the disproportionation reaction are promoted, so that copper powder is precipitated in the plating bath. Therefore, the temperature of the plating bath is 45 to
55 ° C. may be appropriate.
【００３７】[0037]
【実験例５】上述の実施形態に従いながら、以下の表５
に示すような試料を作製した。これらの試料は、無電解
めっき処理におけるエアーの供給量がそれぞれ異なるも
のである。また、この際、めっき浴の温度は５０℃、め
っき時間は６０分間、めっき浴の液量は３．２ｌとし、
めっき浴に添加した硫酸銅の量は０．１０ｍｏｌ／ｌ、
ホルマリン（ホルムアルデヒド）の量は０．２４ｍｏｌ
／ｌ、ＥＤＴＡの量は０．０８ｍｏｌ／ｌとした。[Experimental Example 5] According to the above embodiment, the following Table 5 was used.
Samples as shown in Table 1 were prepared. These samples have different air supply amounts in the electroless plating process. Further, at this time, the temperature of the plating bath was 50 ° C., the plating time was 60 minutes, and the liquid volume of the plating bath was 3.2 l.
The amount of copper sulfate added to the plating bath was 0.10 mol / l,
0.24 mol of formalin (formaldehyde)
/ L and the amount of EDTA were 0.08 mol / l.
【００３８】[0038]
【表５】 [Table 5]
【００３９】表５に示すように、めっき浴１ｌあたりの
エアーの供給量が３７．５ｌ／ｈｒよりも少ない場合
は、不均化反応によって生じたＣｕ2Ｏを再びＣｕに酸
化するのに十分な酸素が供給されず、不均化反応が進
み、めっき浴中に銅粉が析出する。一方、１３１ｌ／ｈ
ｒよりも多い場合は、析出したＣｕが酸化されめっき外
観が黒くなるとともに、析出したＣｕが再溶解し、めっ
き膜厚が低下する。したがって、めっき浴へのエアー供
給量は、めっき浴１ｌあたり３７．５〜１３１ｌ／ｈｒ
が適当である。As shown in Table 5, when the supply amount of air per liter of the plating bath is less than 37.5 l / hr, it is enough to oxidize Cu 2 O generated by the disproportionation reaction to Cu again. Oxygen is not supplied, the disproportionation reaction proceeds, and copper powder precipitates in the plating bath. On the other hand, 131 l / h
If it is larger than r, the deposited Cu is oxidized and the plating appearance becomes black, and the deposited Cu is redissolved and the plating film thickness is reduced. Therefore, the amount of air supplied to the plating bath is 37.5 to 131 l / hr per liter of the plating bath.
Is appropriate.
【００４０】[0040]
【発明の効果】以上のように、この発明によれば、めっ
き浴の成分を補充することなく、めっき開始時に必要な
量のみを添加することによって、１回のめっき処理ごと
にめっき成分を使い切る方法を用いるため、還元反応生
成物がめっき浴中に蓄積しにくい。As described above, according to the present invention, only the necessary amount is added at the start of plating without replenishing the components of the plating bath, so that the plating components can be used up in each plating process. Since the method is used, it is difficult for reduction reaction products to accumulate in the plating bath.
【００４１】また、不均化反応を抑制するような温度領
域、エアー供給量、金属イオン添加量、還元剤添加量、
錯化剤添加量において、無電解めっき処理を行うため、
不均化反応等によって生じた銅粉がめっき浴中に蓄積し
にくい。したがって、めっき浴中に不純物が増加するこ
ともなく、添加した銅イオンの析出効率も上昇し、経済
的である。In addition, a temperature range in which the disproportionation reaction is suppressed, an air supply amount, a metal ion addition amount, a reducing agent addition amount,
In order to perform electroless plating at the amount of complexing agent added,
Copper powder generated by the disproportionation reaction or the like hardly accumulates in the plating bath. Therefore, there is no increase in impurities in the plating bath, and the precipitation efficiency of the added copper ions increases, which is economical.
【００４２】さらに、銅の析出効率が高いため、めっき
浴中に銅イオンがあまり残留せず、錯化剤であるＥＤＴ
Ａの回収効率が上昇する。Further, because of high copper deposition efficiency, little copper ions remain in the plating bath and the complexing agent EDT
The recovery efficiency of A increases.
Claims (11)
を含む無電解めっき浴を用意する工程と、前記無電解め
っき浴を用いて無電解めっきを行う工程とを有する無電
解めっき方法において、 前記無電解めっき浴を用意する工程における無電解めっ
き浴の還元剤の含有量を、前記無電解めっきを行う工程
でのめっき終了時に還元剤が消費し尽くされる量とした
ことを特徴とする無電解めっき方法。1. An electroless plating method comprising: providing an electroless plating bath containing a metal ion, a complexing agent, a reducing agent, and a pH adjuster; and performing an electroless plating using the electroless plating bath. In the method, the content of the reducing agent in the electroless plating bath in the step of preparing the electroless plating bath is an amount by which the reducing agent is consumed at the end of plating in the step of performing the electroless plating. Electroless plating method.
を含む無電解めっき浴を用意する工程と、前記無電解め
っき浴を用いて無電解めっきを行う工程とを有する無電
解めっき方法において、 前記無電解めっき浴を用意する工程における無電解めっ
き浴の金属イオンの含有量を、前記無電解めっきを行う
工程でのめっき終了時に金属イオンが被めっき物表面に
析出し尽くす量としたことを特徴とする無電解めっき方
法。2. An electroless plating method comprising: preparing an electroless plating bath containing a metal ion, a complexing agent, a reducing agent, and a pH adjuster; and performing electroless plating using the electroless plating bath. In the method, the content of metal ions in the electroless plating bath in the step of preparing the electroless plating bath, and the amount by which metal ions are completely deposited on the surface of the object to be plated at the end of plating in the step of performing the electroless plating. An electroless plating method characterized in that:
を含む無電解めっき浴を用意する工程と、前記無電解め
っき浴を用いて無電解めっきを行う工程とを有する無電
解めっき方法において、 前記無電解めっき浴を用意する工程における無電解めっ
き浴の還元剤の含有量を、前記無電解めっきを行う工程
でのめっき終了時に還元剤が消費し尽くされる量とし、
前記無電解めっき浴を用意する工程における無電解めっ
き浴の金属イオンの含有量を、前記無電解めっきを行う
工程でのめっき終了時に金属イオンが被めっき物表面に
析出し尽くす量としたことを特徴とする無電解めっき方
法。3. An electroless plating method comprising the steps of: preparing an electroless plating bath containing a metal ion, a complexing agent, a reducing agent, and a pH adjuster; and performing electroless plating using the electroless plating bath. In the method, the content of the reducing agent in the electroless plating bath in the step of preparing the electroless plating bath is an amount by which the reducing agent is consumed at the end of plating in the step of performing the electroless plating,
The content of metal ions in the electroless plating bath in the step of preparing the electroless plating bath is defined as an amount at which metal ions are completely deposited on the surface of the workpiece at the end of plating in the step of performing the electroless plating. Characteristic electroless plating method.
を含む無電解めっき浴において、還元剤の含有量をめっ
き終了時に還元剤が消費し尽くされる量としたことを特
徴とする無電解めっき浴。4. An electroless plating bath containing a metal ion, a complexing agent, a reducing agent, and a pH adjuster, wherein the content of the reducing agent is set to an amount such that the reducing agent is consumed at the end of plating. Electroless plating bath.
を含む無電解めっき浴において、金属イオンの含有量を
めっき終了時に金属イオンが被めっき物表面に析出し尽
くす量としたことを特徴とする無電解めっき浴。5. An electroless plating bath containing a metal ion, a complexing agent, a reducing agent, and a pH adjuster, wherein the content of the metal ion is an amount at which the metal ion is completely deposited on the surface of the object to be plated at the end of plating. Electroless plating bath characterized by the following.
を含む無電解めっき浴において、還元剤の含有量をめっ
き終了時に還元剤が消費し尽くされる量とし、金属イオ
ンの含有量をめっき終了時に金属イオンが被めっき物表
面に析出し尽くす量としたことを特徴とする無電解めっ
き浴。6. An electroless plating bath containing a metal ion, a complexing agent, a reducing agent and a pH adjuster, wherein the content of the reducing agent is an amount at which the reducing agent is consumed at the end of plating, and the content of the metal ion is An electroless plating bath characterized in that the amount is such that metal ions are completely deposited on the surface of the object to be plated at the end of plating.
２ｍｏｌ／ｌとすることを特徴とする、請求項５または
６に記載の無電解めっき浴。7. A metal ion content of from 0.06 to 0.1
The electroless plating bath according to claim 5 or 6, wherein the concentration is 2 mol / l.
還元するのに必要な理論量の１．２〜２．０倍とするこ
とを特徴とする、請求項７に記載の無電解めっき浴。8. The electroless device according to claim 7, wherein the content of the reducing agent is 1.2 to 2.0 times the theoretical amount required for reducing the contained metal ions. Plating bath.
錯化するのに必要な理論量の０．６〜０．９倍とするこ
とを特徴とする、請求項７または８に記載の無電解めっ
き浴。9. The method according to claim 7, wherein the content of the complexing agent is 0.6 to 0.9 times the theoretical amount required for complexing the contained metal ions. Electroless plating bath as described.
ることを特徴とする、請求項４ないし９記載の無電解め
っき浴。10. The electroless plating bath according to claim 4, wherein the temperature of the plating bath is 45 to 55 ° C.
に、めっき浴１ｌあたり３７．５〜１３１ｌ／ｈｒのエ
アーを通気しながら無電解めっきを行う無電解めっき方
法。11. An electroless plating method in which electroless plating is performed while air is passed through the electroless plating bath of 37.5 to 131 l / hr per liter of the plating bath.
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|---|---|---|---|
| JP11011959A JP2000212761A (en) | 1999-01-20 | 1999-01-20 | Electroless plating method and electroless plating bath |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
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| JP2000212761A true JP2000212761A (en) | 2000-08-02 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6201029B1 (en) * | 2016-12-26 | 2017-09-20 | 日本エレクトロプレイテイング・エンジニヤース株式会社 | Electroless platinum plating solution and electroless platinum plating method |
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1999
- 1999-01-20 JP JP11011959A patent/JP2000212761A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6201029B1 (en) * | 2016-12-26 | 2017-09-20 | 日本エレクトロプレイテイング・エンジニヤース株式会社 | Electroless platinum plating solution and electroless platinum plating method |
| JP2018104755A (en) * | 2016-12-26 | 2018-07-05 | 日本エレクトロプレイテイング・エンジニヤース株式会社 | Electroless platinum plating solution and electroless platinum plating method |
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