JP3162243B2 - Electroless plating method - Google Patents
Electroless plating methodInfo
- Publication number
- JP3162243B2 JP3162243B2 JP05738994A JP5738994A JP3162243B2 JP 3162243 B2 JP3162243 B2 JP 3162243B2 JP 05738994 A JP05738994 A JP 05738994A JP 5738994 A JP5738994 A JP 5738994A JP 3162243 B2 JP3162243 B2 JP 3162243B2
- Authority
- JP
- Japan
- Prior art keywords
- plating
- plating solution
- reducing agent
- metal ion
- electroless
- 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.)
- Expired - Fee Related
Links
Description
【０００１】[0001]
【産業上の利用分野】本発明は無電解めっき方法に関
し、特に無電解めっき反応の進行に伴い生成する副生成
物イオンのめっき液中への蓄積を防ぎ、無電解めっき液
中の塩濃度を一定値以下に保ってめっきを行う無電解め
っき方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroless plating method, and more particularly to a method for preventing by-product ions generated as the electroless plating reaction proceeds from accumulating in a plating solution and reducing the salt concentration in the electroless plating solution. The present invention relates to an electroless plating method for performing plating while maintaining the value at a predetermined value or less.
【０００２】[0002]
【従来の技術】無電解めっき液は通常、金属イオン、金
属イオンの錯化剤、金属イオンの還元剤、及びｐＨ調整
剤を含んでいる。無電解めっきを連続して行うために
は、めっき反応の進行に伴い消費される金属イオン、金
属イオンの還元剤、及びｐＨ調整剤を補給する必要があ
る。めっき液中では、この補給に伴い金属イオンの対陰
イオン、金属イオン還元剤の酸化体イオン、ｐＨ調整剤
の陽イオンが蓄積する。これらイオンが蓄積すると、め
っき膜の物性（特にめっき膜の伸び率）が低下するとい
う問題が生じる。また、無電解めっき液の安定性も低下
し、異常析出や自己分解の原因となる。2. Description of the Related Art Electroless plating solutions usually contain metal ions, metal ion complexing agents, metal ion reducing agents, and pH adjusters. In order to continuously perform electroless plating, it is necessary to replenish metal ions, a reducing agent for metal ions, and a pH adjuster that are consumed as the plating reaction proceeds. In the plating solution, a counter anion of a metal ion, an oxidant ion of a metal ion reducing agent, and a cation of a pH adjusting agent accumulate with the replenishment. When these ions accumulate, there arises a problem that the physical properties of the plated film (particularly, the elongation rate of the plated film) are reduced. Further, the stability of the electroless plating solution is reduced, which causes abnormal deposition and self-decomposition.
【０００３】従来、このような問題を回避するために、
短い使用期間でめっき液を更新したり、劣化しためっき
液に新しいめっき液を連続的に加え、めっき液中の塩濃
度を一定値以下に保つ方法がとられてきた。このような
方法では、高価な無電解めっき液を大量に必要とし、か
つ廃液の処理に膨大な労力と費用が費やされる。また、
地球環境保護の観点からも、多量の金属イオン、金属イ
オンの錯化剤、金属イオンの還元剤等を含んだめっき液
の廃棄は好ましくない。Conventionally, in order to avoid such a problem,
A method has been adopted in which the plating solution is renewed within a short period of use, or a new plating solution is continuously added to the deteriorated plating solution to keep the salt concentration in the plating solution below a certain value. In such a method, a large amount of expensive electroless plating solution is required, and enormous labor and cost are required for treating the waste solution. Also,
From the viewpoint of protection of the global environment, it is not preferable to dispose of a plating solution containing a large amount of metal ions, metal ion complexing agents, metal ion reducing agents, and the like.
【０００４】一方、蓄積イオンを電気透析法により連続
的に除去する方法が、特開昭５６−１３６９６７号公報
に記載されている。しかし、電気透析法では透析の最適
ｐＨに合わせるための煩雑な操作が必要となる。また、
めっき妨害イオンのみを透過させるイオン選択性膜は非
常に高価であり、かつ、機械的強度が弱いため保守管理
が非常に困難である。従って装置全体に掛かるコストが
膨大であるという問題がある。On the other hand, a method of continuously removing accumulated ions by an electrodialysis method is described in Japanese Patent Application Laid-Open No. 56-13667. However, in the electrodialysis method, a complicated operation for adjusting to the optimum pH for dialysis is required. Also,
An ion-selective membrane that allows only plating disturbing ions to permeate is very expensive and has very low mechanical strength, making maintenance and management very difficult. Therefore, there is a problem that the cost for the entire apparatus is enormous.
【０００５】[0005]
【発明が解決しようとする課題】無電解めっきを連続的
に行うと、無電解めっきの副生成物イオンが蓄積する。
この蓄積は正常なめっき膜を形成する無電解めっき反応
を妨害し、めっき膜の品質低下をもたらす。これはめっ
き膜の機械的物性の低下のみではなく、同時に不必要部
に金属が析出する異常析出現象を伴う。しかし、現在ま
でのところ、これらめっき妨害イオンの蓄積を防止する
方法、あるいは蓄積しためっき妨害イオンを除去し、め
っき液を再生する有効な方法は知られていない。When electroless plating is continuously performed, by-product ions of the electroless plating are accumulated.
This accumulation hinders the electroless plating reaction that forms a normal plating film, resulting in deterioration of the quality of the plating film. This involves not only a decrease in the mechanical properties of the plating film, but also an abnormal deposition phenomenon in which metal is deposited in unnecessary portions. However, up to now, there is no known method for preventing the accumulation of these plating interference ions or an effective method for removing the accumulated plating interference ions and regenerating the plating solution.
【０００６】めっき液中に蓄積する金属イオン還元剤の
酸化体イオン濃度としては、０．７モル／ｌ以下が好ま
しく、更に好ましくは０．４モル／ｌ以下である。本発
明の目的は、簡便な操作により、無電解めっき液中に蓄
積する金属イオン還元剤の酸化体イオン、ｐＨ調整剤の
陽イオン等のめっき妨害イオンを除去し、無電解めっき
液中の塩濃度を一定値以下に保ってめっきする方法を提
供することにある。[0006] The oxidant ion concentration of the metal ion reducing agent accumulated in the plating solution is preferably 0.7 mol / l or less, more preferably 0.4 mol / l or less. An object of the present invention is to remove plating disturbing ions such as oxidant ions of a metal ion reducing agent and cations of a pH adjuster which accumulate in an electroless plating solution by a simple operation, and remove a salt in the electroless plating solution. An object of the present invention is to provide a method of plating while keeping the concentration at a certain value or less.
【０００７】[0007]
【課題を解決するための手段】前記したごとく、無電解
めっき反応を連続して行った場合に無電解めっき液中に
蓄積するめっき妨害イオンは、金属イオンの対陰イオ
ン、金属イオン還元剤の酸化体イオン、ｐＨ調整剤の陽
イオンである。金属イオンの対陰イオンは、金属イオン
の補給に可溶性の金属酸化物あるいは水酸化物を使用す
ることで防止することができる。従って、金属イオン還
元剤の酸化体イオン及びｐＨ調整剤の陽イオンの蓄積を
防止することが特に重要な課題である。As described above, when the electroless plating reaction is continuously performed, the plating disturbing ions accumulated in the electroless plating solution are counter anions of metal ions and metal ion reducing agents. It is an oxidant ion and a cation of a pH adjuster. Counter anions of metal ions can be prevented by using soluble metal oxides or hydroxides to replenish the metal ions. Therefore, it is particularly important to prevent accumulation of oxidant ions of the metal ion reducing agent and cations of the pH adjuster.
【０００８】本発明においては、金属イオン還元剤の酸
化体イオンとｐＨ調整剤の陽イオンの組合せを選定し、
これらのイオンを塩として沈殿させ、その沈殿を除去す
ることにより、前記目的を達成する。すなわち、本発明
では、金属イオン還元剤の酸化体イオンとｐＨ調整剤の
陽イオンとで形成される塩が、水溶液中への溶解度が小
さい難溶性塩となるように前記組合せを選定する。In the present invention, a combination of an oxidant ion of a metal ion reducing agent and a cation of a pH adjuster is selected,
The above object is achieved by precipitating these ions as salts and removing the precipitate. That is, in the present invention, the combination is selected so that the salt formed by the oxidant ion of the metal ion reducing agent and the cation of the pH adjuster is a poorly soluble salt having low solubility in an aqueous solution.
【０００９】前記難溶性塩の除去は、前記金属イオン還
元剤の酸化体イオンの蓄積によりめっき膜の品質を低下
させる濃度範囲において、めっき温度又はめっき温度よ
りも低い温度で飽和させて沈澱を生じさせ、その沈澱物
を除去することにより行うことができる。沈澱の生成は
めっき液を濃縮することにより行ってもよい。また、前
記難溶性塩の除去は、無電解めっき液中に所定量の金属
イオン還元剤の酸化体イオンが蓄積した後にめっき処理
を停止して行ってもよいし、めっき液を循環させること
によりめっき処理と並行して行ってもよい。[0009] The removal of the hardly soluble salt can be achieved by saturating at a plating temperature or a temperature lower than the plating temperature within a concentration range in which the quality of the plated film is deteriorated due to accumulation of oxidant ions of the metal ion reducing agent. And removing the precipitate. The precipitation may be performed by concentrating the plating solution. Further, the removal of the hardly soluble salt may be performed by stopping the plating process after a predetermined amount of oxidant ions of the metal ion reducing agent is accumulated in the electroless plating solution, or by circulating the plating solution. It may be performed in parallel with the plating process.
【００１０】[0010]
【作用】例として無電解銅めっきの場合について簡単に
述べる。銅イオンの還元剤としてグリオキシル酸を用い
た場合、グリオキシル酸はめっき液中ではグリオキサレ
ートイオンの形で存在し、下式の反応により酸化体イオ
ンであるしゅう酸イオンを生じる。 ２ＣＨＯＣＯＯ-＋４ＯＨ-→２（ＣＯＯ）2 2-＋２ｅ-＋
２Ｈ2Ｏ＋Ｈ2 The function of electroless copper plating will be briefly described as an example. When glyoxylic acid is used as a copper ion reducing agent, glyoxylic acid is present in the form of glyoxalate ion in the plating solution, and oxalate ion, which is an oxidant ion, is generated by the following reaction. 2CHOCOO − + 4OH − → 2 (COO) 2 2− + 2e − +
2H 2 O + H 2
【００１１】ｐＨ調整剤として水酸化ナトリウムを用い
れば、しゅう酸ナトリウムの溶解度は７０℃で５．０５
ｇ／１００ｇ、２５℃で３．４８ｇ／１００ｇと非常に
小さいため、容易に沈殿として除去することが可能とな
る。これによりめっき液中のイオン濃度を低い値に保つ
ことができ、めっき液の寿命を大幅に延長できる。If sodium hydroxide is used as a pH adjuster, the solubility of sodium oxalate is 5.05 at 70 ° C.
g / 100 g and 3.48 g / 100 g at 25 ° C. are very small, so that they can be easily removed as a precipitate. Thereby, the ion concentration in the plating solution can be kept at a low value, and the life of the plating solution can be greatly extended.
【００１２】すなわち、組合せとして、銅イオン還元剤
としてグリオキシル酸、ｐＨ調整剤の陽イオンとしてナ
トリウムを選ぶことで、めっき液中へのしゅう酸イオン
の蓄積を防止することができるわけである。しゅう酸イ
オンとの組合せとしては、水酸化リチウム等リチウムを
陽イオンとして有するｐＨ調整剤も有効である。もちろ
ん金属イオン還元剤とｐＨ調整剤の組合せは上記に限ら
ない。That is, by selecting glyoxylic acid as a copper ion reducing agent and sodium as a cation of a pH adjuster as a combination, accumulation of oxalate ions in a plating solution can be prevented. As a combination with oxalate ions, a pH adjuster having lithium as a cation, such as lithium hydroxide, is also effective. Of course, the combination of the metal ion reducing agent and the pH adjusting agent is not limited to the above.
【００１３】[0013]
【実施例】以下、本発明の実施例について説明する。比
較例は、従来の無電解めっき方法を説明するものであ
る。 〔実施例１〕銅イオン還元剤としてグリオキシル酸を用
い、ｐＨ調整剤として水酸化ナトリウムを用いて無電解
銅めっきを行った。めっき液の組成及びめっき条件を以
下に示す。Embodiments of the present invention will be described below. The comparative example illustrates a conventional electroless plating method. [Example 1] Electroless copper plating was performed using glyoxylic acid as a copper ion reducing agent and sodium hydroxide as a pH adjuster. The composition of the plating solution and the plating conditions are shown below.
【００１４】 ［めっき液組成］ ・硫酸銅５水和物 ０．０４モル／ｌ ・エチレンジアミン四酢酸二ナトリウム ０．１モル／ｌ ・グリオキシル酸 ０．０３モル／ｌ ・水酸化ナトリウム ０．１モル／ｌ ・２，２’−ビピリジル ０．０００２モル／ｌ ・ポリエチレングリコール（平均分子量６００） ０．０３モル／ｌ ［めっき条件］ ・ｐＨ １２．５ ・液温 ７０℃ 上記無電解銅めっき液で、試験基板上に無電解銅めっき
によるパターン形成を行い、銅の異常析出の有無からめ
っき液の安定性及びめっき膜品質を評価した。試験基板
の作成法は以下に示す。[Plating Solution Composition] Copper sulfate pentahydrate 0.04 mol / l Disodium ethylenediaminetetraacetate 0.1 mol / l Glyoxylic acid 0.03 mol / l Sodium hydroxide 0.1 mol / 2 -2,2'-bipyridyl 0.0002 mol / l -Polyethylene glycol (average molecular weight 600) 0.03 mol / l [Plating conditions] -pH 12.5 -Liquid temperature 70 ° C With the above electroless copper plating solution Then, a pattern was formed on the test substrate by electroless copper plating, and the stability of the plating solution and the quality of the plating film were evaluated based on the presence or absence of abnormal copper deposition. The method of preparing the test substrate is described below.
【００１５】［試験基板作成法］厚さ０．６ｍｍのガラ
ス布入りポリイミド樹脂積層板の両面に、アクリロニト
リルブタジエンゴム変性フェノール樹脂を主成分とする
接着剤を塗布した後、１６０℃で１０分間加熱して硬化
し、厚さ約３０μｍの接着剤層付きの積層板を得た。次
いで、必要箇所にドリルにより穴をあけた後、無水クロ
ム酸及び塩酸を含む粗化液に浸漬して接着剤表面を粗化
した。[Test Board Preparation Method] An adhesive mainly composed of acrylonitrile-butadiene rubber-modified phenol resin was applied to both sides of a 0.6 mm-thick polyimide resin laminate containing glass cloth, and then heated at 160 ° C. for 10 minutes. Then, a laminate having an adhesive layer having a thickness of about 30 μm was obtained. Next, after drilling holes at required places, the surface of the adhesive was roughened by immersion in a roughening solution containing chromic anhydride and hydrochloric acid.
【００１６】次に、無電解銅めっきの触媒として１液性
のパラジウムコロイド触媒溶液〔日立化成工業（株）製
増感剤ＨＳ１０１Ｂを含む酸性水溶液〕に１０分間浸漬
し、水洗を行った後、希塩酸を主成分とする促進処理液
で５分間処理し、水洗の後、１２０℃で２０分間乾燥し
た。このようにして用意した基板の両面に厚さ３５μｍ
のドライフィルムフォトレジストＳＲ−３０００（日立
化成工業）をラミネートし、幅６０μｍの配線を有する
試験パターンのマスクを用いて露光、現像を行い、基板
表面のパターン部以外をレジストによって被覆した。Next, as a catalyst for electroless copper plating, it is immersed in a one-part palladium colloid catalyst solution (an acidic aqueous solution containing a sensitizer HS101B manufactured by Hitachi Chemical Co., Ltd.) for 10 minutes, and washed with water. The substrate was treated with an accelerating treatment solution containing dilute hydrochloric acid as a main component for 5 minutes, washed with water, and dried at 120 ° C. for 20 minutes. 35 μm thick on both sides of the substrate thus prepared
Was laminated, and exposed and developed using a mask of a test pattern having a wiring of 60 μm in width, and the substrate was covered with a resist except for the pattern portion on the substrate surface.
【００１７】以上のように作成した試験基板と同時に、
ステンレス板をめっき液中に浸漬し、液温７０℃、負荷
１ｄｍ2／ｌで無電解銅めっきを施した。ステンレス板
は予め１７％塩酸水溶液中に２分間浸漬し、次いで上述
のパラジウムコロイド溶液に１０分間浸漬した後、水洗
したものを用いた。めっき中は、常時空気を吹き込んで
めっき液を撹拌した。めっき中、銅イオン濃度、グリオ
キシル酸（銅イオン還元剤）濃度及びｐＨが一定になる
ように随時補給した。補給に用いた補給液を以下に示
す。At the same time as the test board prepared as described above,
The stainless plate was immersed in a plating solution, and subjected to electroless copper plating at a solution temperature of 70 ° C. and a load of 1 dm 2 / l. The stainless plate was previously immersed in a 17% hydrochloric acid aqueous solution for 2 minutes, then immersed in the above-mentioned palladium colloid solution for 10 minutes, and then washed with water. During plating, air was constantly blown to stir the plating solution. During plating, replenishment was carried out at any time so that the copper ion concentration, glyoxylic acid (copper ion reducing agent) concentration and pH became constant. The replenisher used for replenishment is shown below.
【００１８】（１）銅イオン補給液 ＣｕＳＯ4・５Ｈ2Ｏ ２００ｇ 水 １ｌとするに必要な量 （２）グリオキシル酸（銅イオン還元剤）補給液 ４０％グリオキシル酸溶液 （３）ｐＨ調整剤 ＮａＯＨ ２００ｇ 水 １ｌとするに必要な量(1) Copper ion replenishing solution CuSO 4 .5H 2 O 200 g Amount required to make water 1 liter (2) Glyoxylic acid (copper ion reducing agent) replenishing solution 40% glyoxylic acid solution (3) pH adjuster NaOH 200 g Water 1 l
【００１９】ステンレス板上及び試験基板のパターン部
に３０μｍの厚さにめっきすることを、めっき１回とし
た。各回が終了する毎に、ステンレス板よりめっき皮膜
を剥離して、１．２５ｃｍ×１０ｃｍの大きさに切断
し、めっき皮膜の機械的強度を通常の引っ張り試験機で
測定した。また、めっき液は各回のめっき終了後、一旦
室温（２５℃）に戻し、しゅう酸ナトリウムの沈殿を濾
過した後、次回のめっきを行った。濾過した後のめっき
液中のしゅう酸イオン濃度はクロマトグラフにより定量
した。Plating on a stainless plate and a pattern portion of a test substrate to a thickness of 30 μm was defined as one plating. Each time the process was completed, the plating film was peeled off from the stainless steel plate, cut into a size of 1.25 cm × 10 cm, and the mechanical strength of the plating film was measured with a normal tensile tester. Further, the plating solution was returned to room temperature (25 ° C.) once after each plating, and the precipitate of sodium oxalate was filtered, and then the next plating was performed. The oxalate ion concentration in the plating solution after filtration was quantified by chromatography.
【００２０】測定結果を図１の表に示す。めっき液中の
しゅう酸イオン濃度は、各回のめっき終了後の濾過を行
った後の測定結果である。７回のめっきを行った後で
も、しゅう酸イオン濃度は０．２５ｍｏｌ／ｌであり、
メッキ膜の伸び率は６．１％を示し、異常析出は全く認
められなかった。このように、本発明の方法によりめっ
き液中へのしゅう酸イオンの蓄積が完全に抑制できてい
ることが明らかである。The measurement results are shown in the table of FIG. The oxalate ion concentration in the plating solution is a measurement result after filtration after completion of each plating. Even after performing the plating seven times, the oxalate ion concentration is 0.25 mol / l,
The elongation of the plated film was 6.1%, and no abnormal deposition was observed. Thus, it is clear that the method of the present invention can completely suppress the accumulation of oxalate ions in the plating solution.
【００２１】〔実施例２〕めっき液中の銅イオン濃度を
一定に保つための銅イオンの補給を酸化銅粉末で行った
以外は、全て実施例１と同様の条件で無電解銅めっきを
行った。その結果を図１の表に示す。酸化銅を用いるこ
とで銅イオンの対陰イオンの蓄積も防止することがで
き、めっき膜の品質もより長期間にわたり高品質を維持
することができた。また、銅イオンの補給に水酸化銅を
用いた場合も同様に良好な結果が得られた。Example 2 Electroless copper plating was performed under the same conditions as in Example 1 except that copper ions were replenished with copper oxide powder to keep the copper ion concentration in the plating solution constant. Was. The results are shown in the table of FIG. By using copper oxide, the accumulation of counter anions of copper ions could be prevented, and the quality of the plating film could be maintained for a longer period of time. Similarly, good results were obtained when copper hydroxide was used to supply copper ions.
【００２２】〔比較例１〕銅イオン還元剤としてホルム
アルデヒドを用い、ｐＨ調整剤として水酸化ナトリウム
を用いる従来のめっき液により無電解銅めっきを行っ
た。めっき液のｐＨは１２．５、液温は７０℃とした。
この場合、還元剤のホルムアルデヒドの酸化体イオン
は、ぎ酸イオンであり、ぎ酸ナトリウムの溶解度は水１
００ｇ中に９９．６ｇ（２５℃）と極めて大きい。従っ
て、めっき液の冷却後においても、ぎ酸ナトリウムの沈
殿は発生せず、ぎ酸イオンを除去することはできなかっ
た。Comparative Example 1 Electroless copper plating was performed using a conventional plating solution using formaldehyde as a copper ion reducing agent and sodium hydroxide as a pH adjuster. The plating solution had a pH of 12.5 and a solution temperature of 70 ° C.
In this case, the oxidant ion of formaldehyde as the reducing agent is formate ion, and the solubility of sodium formate is water 1
It is extremely large at 99.6 g (25 ° C.) in 00 g. Therefore, even after cooling of the plating solution, precipitation of sodium formate did not occur, and formate ions could not be removed.
【００２３】繰り返しめっきによるめっき液中のぎ酸イ
オン濃度、及びめっき膜品質の変化を図１の表に示し
た。繰り返しめっき回数が進むにつれ、めっき液中で、
ぎ酸イオン濃度が増加し、めっき膜の伸び率が低下して
いることが分かる。また、めっき液の安定性も劣化し、
５回目のめっき途中でめっき液は自己分解を起こし、め
っき不能となった。FIG. 1 shows the change in the concentration of formate ion in the plating solution and the quality of the plating film due to the repeated plating. As the number of repeated plating increases,
It can be seen that the formate ion concentration increases and the elongation of the plating film decreases. Also, the stability of the plating solution deteriorates,
The plating solution self-decomposed in the middle of the fifth plating, and plating was impossible.
【００２４】〔比較例２〕実施例１に示した無電解銅め
っき液で、ｐＨ調整剤として水酸化ナトリウムの代わり
に水酸化カリウムを用いて無電解銅めっきを行った。め
っき液のｐＨは１２．５、液温は７０℃とした。この場
合、しゅう酸カリウムの溶解度は水１００ｇ中に３５．
９ｇ（２５℃）と大きいため、めっき液の冷却後におい
てもしゅう酸カリウムの沈殿は発生せず、しゅう酸イオ
ンを除去することはできなかった。Comparative Example 2 Electroless copper plating was performed using the electroless copper plating solution shown in Example 1 but using potassium hydroxide instead of sodium hydroxide as a pH adjuster. The plating solution had a pH of 12.5 and a solution temperature of 70 ° C. In this case, the solubility of potassium oxalate is 35.50 per 100 g of water.
Since it was as large as 9 g (25 ° C.), precipitation of potassium oxalate did not occur even after cooling the plating solution, and oxalate ions could not be removed.
【００２５】繰り返しめっきによるめっき液中のしゅう
酸イオン濃度、及びめっき膜品質の変化を図１の表に示
した。繰り返し回数が進むにつれ、めっき液中にしゅう
酸イオンが蓄積し、めっき膜の伸び率が低下しているこ
とが分かる。また、めっき液の安定性も劣化し、５回目
のめっき途中でめっき液は自己分解を起こし、めっき不
能となった。The change in oxalate ion concentration in the plating solution and the quality of the plating film due to the repeated plating are shown in the table of FIG. It can be seen that as the number of repetitions increases, oxalate ions accumulate in the plating solution, and the elongation rate of the plating film decreases. Further, the stability of the plating solution also deteriorated, and the plating solution self-decomposed in the middle of the fifth plating, making plating impossible.
【００２６】以上のように、本発明によると、めっき液
中へのイオンの蓄積が防止でき、その結果長期間に渡り
良好なめっき膜が得られることが分かった。なお、前記
実施例の組成及び条件のめっきでは、表に示したよう
に、還元剤の酸化体イオン蓄積濃度が約０．３モル／ｌ
以下のとき異常析出の発生も無く良好なめっき膜物性が
得られているが、良好なめっきを行うことができる還元
剤の酸化体イオンの蓄積濃度はめっき条件や被めっき基
板により変化する。従ってこの値は蓄積イオンの濃度限
界の絶対値を表すものではない。As described above, according to the present invention, it was found that accumulation of ions in the plating solution could be prevented, and as a result, a good plating film could be obtained over a long period of time. In the plating of the composition and conditions of the above embodiment, as shown in the table, the oxidant ion accumulation concentration of the reducing agent was about 0.3 mol / l.
In the following cases, good plating film properties are obtained without occurrence of abnormal deposition, but the accumulated concentration of oxidant ions of the reducing agent that enables good plating varies depending on plating conditions and the substrate to be plated. Therefore, this value does not represent the absolute value of the concentration limit of the accumulated ions.
【００２７】〔実施例３〕実施例１に示した無電解銅め
っき液を用いて、冷却槽を装備しためっき装置で得られ
ためっき膜の機械的物性及びめっき液中のしゅう酸イオ
ン濃度の変化について実施例１と同様な検討を行った。
本実施例で使用しためっき装置の概略を図２に示す。無
電解めっき槽１中のめっき液はポンプ２により連続的に
冷却槽３に汲みだされる。冷却槽３は、例えば冷却管を
用いる水冷式のもので、めっき液は約２５℃に冷却され
る。冷却されて沈澱物を生じた冷却槽３中のめっき液
は、ポンプ４によってろ過装置５に移送され、ろ過装置
５のフィルターで沈殿物を除去された後、再びめっき槽
１に戻される。Example 3 Using the electroless copper plating solution shown in Example 1, the mechanical properties and the oxalate ion concentration of the plating film obtained by the plating apparatus equipped with a cooling bath were measured. The change was examined in the same manner as in Example 1.
FIG. 2 schematically shows a plating apparatus used in this embodiment. The plating solution in the electroless plating tank 1 is continuously pumped into the cooling tank 3 by the pump 2. The cooling tank 3 is of a water-cooling type using a cooling pipe, for example, and the plating solution is cooled to about 25 ° C. The plating solution in the cooling tank 3 that has been cooled to produce a precipitate is transferred to the filtration device 5 by the pump 4, the precipitate is removed by the filter of the filtration device 5, and then returned to the plating tank 1 again.
【００２８】このように連続的にしゅう酸ナトリウム沈
殿物の除去を行いながらめっきしたところ、実施例１と
同様、めっき液中へのしゅう酸イオンの蓄積を抑制で
き、良好なめっき膜物性が長期間にわたり得られた。When plating was performed while continuously removing the sodium oxalate precipitate, accumulation of oxalate ions in the plating solution could be suppressed and good physical properties of the plated film could be improved, as in Example 1. Obtained over a period.
【００２９】〔実施例４〕実施例１に示した無電解銅め
っき液を用いて、濃縮槽を装備しためっき装置で得られ
ためっき膜の機械的物性及びめっき液中のしゅう酸イオ
ン濃度の変化について実施例１と同様な検討を行った。Example 4 Using the electroless copper plating solution shown in Example 1, the mechanical properties and the oxalate ion concentration of the plating film obtained by a plating apparatus equipped with a concentration tank were measured. The change was examined in the same manner as in Example 1.
【００３０】本実施例で使用しためっき装置は、図２に
示す装置において冷却槽３を濃縮槽に替えたものに相当
する。無電解めっき槽１中のめっき液はポンプ２により
連続的に濃縮槽（３）に汲みだされて加熱蒸発によって
濃縮される。濃縮されて沈澱物を生じた濃縮槽（３）中
のめっき液は、ポンプ４によってろ過装置５に移送さ
れ、ろ過装置５のフィルターで沈殿物を除去された後、
再びめっき槽１に戻される。尚、濃縮槽でめっき液は約
３倍以上に濃縮される。このように連続的にしゅう酸ナ
トリウム沈殿物の除去を行いながらめっきしたところ、
実施例１と同様、めっき液中へのしゅう酸イオンの蓄積
を抑制でき、良好なめっき膜物性が長期間にわたり得ら
れた。The plating apparatus used in this embodiment corresponds to the apparatus shown in FIG. 2 in which the cooling tank 3 is replaced with a concentration tank. The plating solution in the electroless plating tank 1 is continuously pumped to the concentration tank (3) by the pump 2 and concentrated by heating and evaporating. The plating solution in the concentration tank (3) in which the precipitate has been concentrated is transferred to the filtration device 5 by the pump 4, and after the precipitate is removed by the filter of the filtration device 5,
It is returned to the plating tank 1 again. The plating solution is concentrated about three times or more in the concentration tank. When plating was performed while continuously removing the sodium oxalate precipitate,
As in Example 1, accumulation of oxalate ions in the plating solution could be suppressed, and good plating film properties were obtained over a long period of time.
【００３１】〔実施例５〕実施例１に示した無電解銅め
っき液で、ｐＨ調整剤として水酸化ナトリウムの代わり
に水酸化リチウムを用いて実施例１と同様な検討を行っ
た。この場合、しゅう酸リチウムの溶解度は水１００ｇ
中に５．８７ｇ（２５℃）と比較的小さいため、実施例
１と同様、めっき液中へのしゅう酸イオンの蓄積を抑制
でき、良好な品質を有するめっき膜が長期間にわたり得
られた。Example 5 The same study as in Example 1 was conducted using the electroless copper plating solution shown in Example 1 but using lithium hydroxide instead of sodium hydroxide as a pH adjuster. In this case, the solubility of lithium oxalate is 100 g of water.
Since it was relatively small at 5.87 g (25 ° C.), accumulation of oxalate ions in the plating solution could be suppressed as in Example 1, and a plated film having good quality was obtained over a long period of time.
【００３２】〔実施例６〕ほう水素化ナトリウムを還元
剤として、ニッケルの無電解めっきを試みた。ｐＨ調整
剤としては水酸化リチウムを用いた。めっき液組成及び
めっき条件を以下に示す。 ［めっき液組成］ ・塩化ニッケル ０．１３モル／ｌ ・エチレンジアミン ０．２５モル／ｌ ・水酸化リチウム １．０モル／ｌ ・ほう水素化ナトリウム ０．０１５モル／ｌ ［めっき条件］ ・ｐＨ １４ ・液温 ９０℃Example 6 Electroless plating of nickel was attempted using sodium borohydride as a reducing agent. Lithium hydroxide was used as a pH adjuster. The plating solution composition and plating conditions are shown below. [Plating solution composition] Nickel chloride 0.13 mol / l Ethylenediamine 0.25 mol / l Lithium hydroxide 1.0 mol / l Sodium borohydride 0.015 mol / l [Plating conditions] pH 14・ Liquid temperature 90 ℃
【００３３】ほう水素化ナトリウムは、めっき液中にお
いて以下に示す反応により、メタほう酸イオンを生じ
る。 ＢＨ4 -＋４ＯＨ-→ＢＯ2 -＋２Ｈ2＋２Ｈ2Ｏ＋４ｅ- ｐＨ調整剤として水酸化リチウムを用いた場合、メタほ
う酸リチウムの溶解度は水１００ｇ中に３．３４ｇ（２
５℃）と比較的小さいため容易に沈殿として除去でき
る。本実施例によると、得られたニッケルめっき膜の品
質及びめっき液の安定性とも長期間にわたり良好であ
り、めっき液の脱イオン化による長寿命化が達成でき
た。Sodium borohydride generates metaborate ions by the following reaction in the plating solution. BH 4 − + 4OH − → BO 2 − + 2H 2 + 2H 2 O + 4e − When lithium hydroxide is used as the pH adjuster, the solubility of lithium metaborate is 3.34 g in 100 g of water (2
(5 ° C.) and can be easily removed as a precipitate. According to this example, the quality of the obtained nickel plating film and the stability of the plating solution were good over a long period of time, and a long life was achieved by deionization of the plating solution.
【００３４】〔実施例７〕次に、ほう水素化ナトリウム
を還元剤として、コバルトの無電解めっきを試みた。ｐ
Ｈ調整剤としては、水酸化リチウムを用いた。めっき液
組成及びめっき条件を以下に示す。 ［めっき液組成］ ・硫酸コバルト ０．０５モル／ｌ ・エチレンジアミン ０．４モル／ｌ ・ロッセル塩 ０．０６モル／ｌ ・水酸化リチウム ０．８モル／ｌ ・ほう水素化ナトリウム ０．０１５モル／ｌ ［めっき条件］ ・ｐＨ １３．０ ・液温 ７０℃Example 7 Next, electroless plating of cobalt was attempted using sodium borohydride as a reducing agent. p
As the H adjustor, lithium hydroxide was used. The plating solution composition and plating conditions are shown below. [Plating solution composition] Cobalt sulfate 0.05 mol / l Ethylenediamine 0.4 mol / l Rossel salt 0.06 mol / l Lithium hydroxide 0.8 mol / l Sodium borohydride 0.015 mol / L [Plating conditions] ・ pH 13.0 ・ Liquid temperature 70 ℃
【００３５】めっき液中に生じるメタほう酸リチウムの
溶解度は、前述のように水１００ｇ中に３．３４ｇ（２
５℃）と比較的小さいため容易に沈殿として除去でき
る。本実施例においても実施例６同様、得られたコバル
トめっき膜の品質及びめっき液の安定性とも長期間にわ
たり良好であり、めっき液の脱イオン化による長寿命化
が達成できた。As described above, the solubility of lithium metaborate generated in the plating solution was 3.34 g (2
(5 ° C.) and can be easily removed as a precipitate. In this example, as in Example 6, the quality of the obtained cobalt plating film and the stability of the plating solution were good over a long period of time, and a long life was achieved by deionization of the plating solution.
【００３６】[0036]
【発明の効果】本発明によると、無電解めっき反応の進
行に伴い生成する副生成物イオンの蓄積を防ぐことがで
き、無電解めっき液の長寿命化を図ることができる。According to the present invention, the accumulation of by-product ions generated as the electroless plating reaction proceeds can be prevented, and the life of the electroless plating solution can be extended.
【図１】繰り返しめっきによるめっき液中の金属イオン
還元剤の酸化体イオン濃度、及びめっき膜品質の変化を
示す図。FIG. 1 is a graph showing changes in the oxidant ion concentration of a metal ion reducing agent in a plating solution and the quality of a plating film due to repeated plating.
【図２】本実施例で使用しためっき装置の概略図。FIG. 2 is a schematic diagram of a plating apparatus used in the present embodiment.
１…無電解めっき槽、２，４…ポンプ、３…冷却槽（濃
縮槽）、５…ろ過装置1: electroless plating tank, 2, 4: pump, 3: cooling tank (concentration tank), 5: filtration device
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) C23C 18/00 - 18/54 ──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. 7 , DB name) C23C 18/00-18/54
Claims (6)
ｐＨ調整剤を含むめっき液を用いる無電解めっき方法に
おいて、 前記金属イオンの還元剤の酸化体イオンと前記ｐＨ調整
剤を構成する陽イオン成分とがめっき液中へ難溶性塩を
生じるように前記金属イオンの還元剤及び前記ｐＨ調整
剤を選択し、めっき反応の進行に伴いめっき液中に生成
する前記難溶性塩の沈殿を除去することにより無電解め
っき液中の塩濃度を一定値以下に保ってめっきすること
を特徴とする無電解めっき方法。1. An electroless plating method using a plating solution containing a metal ion, a reducing agent for the metal ion, and a pH adjusting agent, wherein an oxidant ion of the reducing agent for the metal ion and a cation constituting the pH adjusting agent The reducing agent for the metal ion and the pH adjuster are selected so that the components form a poorly soluble salt in the plating solution, and the precipitate of the poorly soluble salt generated in the plating solution as the plating reaction proceeds is removed. An electroless plating method characterized in that plating is performed while keeping the salt concentration in the electroless plating solution at a certain value or less.
縮して、前記難溶性塩の沈澱を生じさせることを特徴と
する請求項１記載の無電解めっき方法。2. The electroless plating method according to claim 1, wherein at least a part of the plating solution is cooled or concentrated to cause precipitation of the hardly soluble salt.
サレートイオンを用い、前記ｐＨ調整剤を構成する陽イ
オン成分としてナトリウム又はリチウムを用い、めっき
反応の進行に伴い蓄積する金属イオン還元剤の酸化体イ
オンをナトリウム塩又はリチウム塩として沈殿させるこ
とを特徴とする請求項１又は２記載の無電解めっき方
法。3. A method of using a glyoxalate ion as a reducing agent of the metal ion and using sodium or lithium as a cation component constituting the pH adjusting agent, wherein the oxidation of the metal ion reducing agent accumulates as the plating reaction progresses. 3. The electroless plating method according to claim 1, wherein body ions are precipitated as a sodium salt or a lithium salt.
ｐＨ調整剤を含むめっき液を用いる無電解めっき方法に
おいて、 前記金属イオンの還元剤の酸化体イオンと前記ｐＨ調整
剤を構成する陽イオン成分とがめっき液中へ難溶性塩を
生じるように前記金属イオンの還元剤及び前記ｐＨ調整
剤を選択し、めっき液中に所定量の金属イオン還元剤の
酸化体イオンが蓄積した後にめっき処理を停止し、めっ
き液を冷却又は濃縮することにより、前記金属イオン還
元剤の酸化体イオンをｐＨ調整剤を構成する陽イオンと
の塩として沈殿させ、該沈殿を除去した後、再び無電解
めっきを行うことで、めっき液中の塩濃度を一定値以下
に保ってめっきを行うことを特徴とする無電解めっき方
法。4. An electroless plating method using a plating solution containing a metal ion, a reducing agent for the metal ion and a pH adjusting agent, wherein an oxidant ion of the reducing agent for the metal ion and a cation constituting the pH adjusting agent The metal ion reducing agent and the pH adjuster are selected so that the components form a poorly soluble salt in the plating solution, and after a predetermined amount of oxidant ions of the metal ion reducing agent are accumulated in the plating solution, plating treatment is performed. Is stopped, and the plating solution is cooled or concentrated to precipitate oxidized ions of the metal ion reducing agent as salts with cations constituting the pH adjuster. After removing the precipitate, electroless plating is performed again. By performing plating while maintaining the salt concentration in the plating solution at a certain value or less.
ｐＨ調整剤を含むめっき液を用いる無電解めっき方法に
おいて、 前記金属イオンの還元剤の酸化体イオンと前記ｐＨ調整
剤を構成する陽イオン成分とがめっき液中へ難溶性塩を
生じるように前記金属イオンの還元剤及び前記ｐＨ調整
剤を選択し、めっき液を循環させ、該循環経路中でめっ
き液を冷却又は濃縮することによりめっき液中に不溶性
の沈殿を生じさせ、該沈殿を連続的に除去することによ
りめっき液中の塩濃度を一定値以下に保ってめっきを行
うことを特徴とする無電解めっき方法。5. An electroless plating method using a plating solution containing a metal ion, a reducing agent for the metal ion, and a pH adjusting agent, wherein an oxidant ion of the reducing agent for the metal ion and a cation constituting the pH adjusting agent By selecting the metal ion reducing agent and the pH adjuster such that the components form a poorly soluble salt in the plating solution, circulating the plating solution, and cooling or concentrating the plating solution in the circulation path to perform plating. An electroless plating method, wherein an insoluble precipitate is formed in a solution, and the precipitate is continuously removed to perform plating while keeping a salt concentration in a plating solution at a certain value or less.
を含むめっき液を用いる無電解銅めっき方法において、 めっき反応の進行に伴い減少する銅イオンの補給を酸化
銅又は水酸化銅の少なくとも一方で行い、めっき反応の
進行に伴い蓄積する銅イオン還元剤の酸化体イオンをｐ
Ｈ調整剤を構成する陽イオンとの難溶性塩として沈殿さ
せ、該沈殿を除去することにより、めっき液中への副生
成物イオンの蓄積を防ぎ、めっき液中の塩濃度を一定値
以下に保って銅めっきを行うことを特徴とする無電解銅
めっき方法。6. An electroless copper plating method using a plating solution containing copper ions, a pH adjuster, and a copper ion reducing agent, wherein the supply of copper ions, which decreases with the progress of the plating reaction, is performed using at least copper oxide or copper hydroxide. On the other hand, the oxidant ions of the copper ion reducing agent that accumulate with the progress of the plating reaction are p
By precipitating as a poorly soluble salt with a cation constituting the H adjuster and removing the precipitate, accumulation of by-product ions in the plating solution is prevented, and the salt concentration in the plating solution is kept to a certain value or less. An electroless copper plating method characterized by performing copper plating while maintaining.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP05738994A JP3162243B2 (en) | 1994-03-28 | 1994-03-28 | Electroless plating method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP05738994A JP3162243B2 (en) | 1994-03-28 | 1994-03-28 | Electroless plating method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07268638A JPH07268638A (en) | 1995-10-17 |
| JP3162243B2 true JP3162243B2 (en) | 2001-04-25 |
Family
ID=13054270
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP05738994A Expired - Fee Related JP3162243B2 (en) | 1994-03-28 | 1994-03-28 | Electroless plating method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3162243B2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4482744B2 (en) | 2001-02-23 | 2010-06-16 | 株式会社日立製作所 | Electroless copper plating solution, electroless copper plating method, wiring board manufacturing method |
| US6897152B2 (en) | 2003-02-05 | 2005-05-24 | Enthone Inc. | Copper bath composition for electroless and/or electrolytic filling of vias and trenches for integrated circuit fabrication |
| JP3930832B2 (en) | 2003-06-06 | 2007-06-13 | 株式会社山本鍍金試験器 | Aquarium |
| JP5715411B2 (en) * | 2010-12-28 | 2015-05-07 | ローム・アンド・ハース電子材料株式会社 | Method for removing impurities from plating solution |
| JP5830242B2 (en) * | 2010-12-28 | 2015-12-09 | ローム・アンド・ハース電子材料株式会社 | Method for removing impurities from plating solution |
| JP5937320B2 (en) * | 2011-09-14 | 2016-06-22 | ローム・アンド・ハース電子材料株式会社 | Method for removing impurities from plating solution |
-
1994
- 1994-03-28 JP JP05738994A patent/JP3162243B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07268638A (en) | 1995-10-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3993491A (en) | Electroless plating | |
| JP6066396B2 (en) | Stable catalyst for electroless metallization | |
| TWI629374B (en) | Method of electroless plating | |
| US20120171363A1 (en) | Catalyst application solution, electroless plating method using same, and direct plating method | |
| US4150171A (en) | Electroless plating | |
| JP2002249879A (en) | Electroless copper plating solution, electroless copper plating method and production method for wiring board | |
| JP6444664B2 (en) | Electroless metallization of dielectrics with alkali-stable pyrazine derivative-containing catalysts | |
| US20050252684A1 (en) | Electroless copper plating machine thereof, and multi-layer printed wiring board | |
| JP3162243B2 (en) | Electroless plating method | |
| JP3337802B2 (en) | Direct plating method by metallization of copper (I) oxide colloid | |
| JP3890542B2 (en) | Method for manufacturing printed wiring board | |
| TWI614372B (en) | Method of electroless plating | |
| EP0098472B1 (en) | Method for decreasing plated metal defects by treating a metallic surface | |
| JP4000476B2 (en) | Composition for pretreatment of electroless plating | |
| KR102641509B1 (en) | Method of copper electroplating | |
| TW202208682A (en) | Electroless nickel plating bath | |
| JP2021075785A (en) | Electroless copper plating and preventing passivation | |
| JP2001049448A (en) | Electroless nickel plating method | |
| KR102641511B1 (en) | Electroless plating solution and method of copper electroplating | |
| JP3201269B2 (en) | Regeneration method of electroless plating bath | |
| JPH09137277A (en) | Electroless plating liquid, electroless plating method and production of printed circuit board | |
| JPH0361380A (en) | Electroless tin plating bath | |
| JP3626022B2 (en) | Manufacturing method of multilayer printed wiring board | |
| JP2023008204A (en) | Ni CATALYST SOLUTION FOR ELECTROLESS Ni-P PLATING AND METHOD OF FORMING ELECTROLESS Ni-P PLATING FILM USING THE SAME | |
| JPH0361756B2 (en) |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20080223 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090223 Year of fee payment: 8 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090223 Year of fee payment: 8 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100223 Year of fee payment: 9 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100223 Year of fee payment: 9 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110223 Year of fee payment: 10 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120223 Year of fee payment: 11 |
|
| LAPS | Cancellation because of no payment of annual fees |