JPH02149694A - Plating method - Google Patents

Abstract

PURPOSE:To easily prevent the leaving of an unplated part at a low cost and to enhance yield and productivity when a body having fine holes, recessed part or gaps is plated, by applying ultrasonic waves to the body in a plating soln. and carrying out plating. CONSTITUTION:When a body having fine holes, recessed part or gaps is plated, the body to be plated is immersed in a plating soln. and ultrasonic waves are applied to the body for a certain time during or after immersion to remove air present in the fine holes, etc., of about <=1.0mm size. The body is then subjected to prescribed plating. The leaving of an unplated part due to the air is perfectly prevented.

Description

【発明の詳細な説明】 ［産業上の利用分野］ 本発明は、めっき方法に関し、より詳細には、微小な孔
、凹部乃至間隙を有する被めっき物のめっき方法に係る
。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a plating method, and more particularly, to a method for plating an object to be plated having minute holes, recesses, or gaps.

［従来技術］ トランジスタ、ＩＣ、プリント基板等の電子部品は小型
化のニーズが強く、その形状は複雑化する傾向にある。[Prior Art] There is a strong need for miniaturization of electronic components such as transistors, ICs, and printed circuit boards, and their shapes tend to become more complex.

それに伴い、これら電子部品を搭載乃至接続するリード
フレームやプリント基板その他の部品におけるスルーホ
ール等の微小な孔の直径は一層小さくなりてきている。Along with this, the diameters of minute holes such as through holes in lead frames, printed circuit boards, and other components on which these electronic components are mounted or connected are becoming smaller.

また、用途に応じて微小な凹部乃至間隙を形成すること
が行なわれている。Additionally, minute recesses or gaps are formed depending on the application.

ところで、従来、被めフぎ物のめっき方法としては、脱
脂等の前処理を行なフた後に被めっき物をめフき浴に浸
漬してめっきを行なう方法が行なわれている。By the way, conventionally, as a method for plating the object to be plated, a method has been used in which the object to be plated is immersed in a matting bath after performing pre-treatment such as degreasing.

しかしながら、従来のめつき方法により、微小な孔、凹
部乃至間隙を有する被めっ鎗物のめっぎを行なうと、孔
、凹部乃至間隙にめっきがされない部分すなわち無めっ
き部が生じることがある。However, when a mold to be plated having minute holes, recesses, or gaps is plated using conventional plating methods, unplated portions, that is, unplated portions, may occur in the holes, recesses, or gaps.

かかる無めっき部の発生を防止する対策として、必要以
上に脱脂工程を増加させることやエツチングにより脱脂
性を向上させること、あるいは、めっき液の表面張力を
低下させるために添加剤を加えることなどが行なわれて
いるが、いずれもコスト高や、液の管理の繁雑さを増し
てしまう。のみならず、無めっき部の発生を完全には防
止することができない。Measures to prevent the occurrence of such unplated areas include increasing the number of degreasing steps more than necessary, improving degreasing performance by etching, or adding additives to lower the surface tension of the plating solution. However, all of these methods increase the cost and the complexity of liquid management. Furthermore, the occurrence of unplated areas cannot be completely prevented.

［発明が解決しようとする課題］ 本発明は微小な孔、凹部乃至間隙を有する被めっき物に
対しても無めっぎ部を発生させることなく安価かつ容易
にめっきを行なうことができるめっき方法を提供するこ
とを目的とする。[Problems to be Solved by the Invention] The present invention provides a plating method that can inexpensively and easily plate objects having minute holes, recesses, or gaps without creating unplated areas. The purpose is to provide

［課題を解決するための手段］ 本発明の要旨は、微小な孔、凹部乃至間隙を有する被め
っき物をめっきする方法において、めっき液中で該被め
っき物に超音波を印加した後めっきを行なうことを特徴
とするめつき方法に存在する。[Means for Solving the Problems] The gist of the present invention is to provide a method for plating an object to be plated having minute holes, recesses, or gaps, in which ultrasonic waves are applied to the object to be plated in a plating solution, and then plating is carried out. It exists in a plating method characterized by the following.

［作用］ 以下に本発明の作用を本発明をなすに際して得た知見と
ともに説明する。[Function] The function of the present invention will be explained below along with the findings obtained in making the present invention.

本発明者は、まず、無めりきの発生原因は被めっき物の
脱脂不良にあるのではないかと考え調査した結果、脱脂
不良の影響はあるものの本質的には被めっき物の幾何学
的な形状に起因するところが大きいことがわかった。The inventor of the present invention first thought that the cause of unmetallic spots may be due to insufficient degreasing of the object to be plated, and as a result of investigation, it was found that although the defective degreasing may have an effect, it is essentially due to the geometrical problem of the object to be plated. It turns out that this is largely due to the shape.

さらに調査を行なったところ、被めっき物をめっき液中
に浸漬した時に、微小な孔、凹部乃至間隙には空気が存
在し、この空気は被めっぎ物から離脱することなく存在
し、この空気の存在が無めっき部の発生原因となってい
ることを知見した。Further investigation revealed that when the object to be plated is immersed in the plating solution, air exists in minute holes, recesses, and gaps, and this air exists without leaving the object. It was discovered that the presence of air was the cause of the occurrence of unplated areas.

そこで、本発明者は１．この空気の除去方法を探究し、
第一の試みとして、めっき液への浸漬前に、水中で被め
っき物に超音波を印加し、その後めっき液へ浸漬しめっ
きを行なった。しかし、かかる方法を採用しても無めっ
き部の発生を完全には防止することができなかった。Therefore, the inventors of the present invention 1. Investigating ways to remove this air,
As a first attempt, ultrasonic waves were applied to the object to be plated in water before immersion in the plating solution, and then the object was immersed in the plating solution for plating. However, even if such a method is adopted, it has not been possible to completely prevent the occurrence of unplated areas.

そこで、次なる試みとして、超音波を印加しつつめっき
を行なったところ、超音波特有の縞模様が被めっき物表
面に発生した。すなわち、めっき外観に関する新たな課
題が発生した。Therefore, as a next attempt, when plating was performed while applying ultrasonic waves, a striped pattern peculiar to ultrasonic waves was generated on the surface of the plated object. In other words, a new problem regarding the appearance of the plating has arisen.

さらに、超音波の印加方法について検討を重ねた結果、
めっき液中で被めフき物に超音波を印加し、その後めっ
きを行なえば、無めっき部の発生を防止することができ
、また、Ｎ４模様の発生をも防止することができること
を発見し本発明をなすに至った。Furthermore, as a result of repeated studies on the method of applying ultrasonic waves,
We discovered that by applying ultrasonic waves to the coated material in a plating solution and then plating, it is possible to prevent the occurrence of unplated areas and also to prevent the occurrence of N4 patterns. The present invention has been accomplished.

超音波の印加による気泡の離脱効果については超音波の
物理的な振動によるものと考えられるので、超音波振動
子を被めっき物に対面させて効率よく印加すればよりよ
く気泡の離脱を行なうことができる。超音波の印加方法
としては、めっぎ液中に被めっき物を浸漬しながら印加
する方法、あるいは、めっき液中に被めっき物を浸漬し
た後に一定時間印加する方法のいずれでも良い、いずれ
の方法でも短時間の印加にて十分である。このため、超
音波装置を付加するのみで、他の工程上の変更を必要と
せず、容易に無めっき部の発生を防止することができる
。The effect of removing bubbles due to the application of ultrasonic waves is thought to be due to the physical vibration of the ultrasonic waves, so if the ultrasonic vibrator is placed facing the object to be plated and the application is applied efficiently, the bubbles will be removed more effectively. Can be done. The method of applying ultrasonic waves may be either by applying the ultrasound while the object to be plated is immersed in the plating solution, or by applying the ultrasound for a certain period of time after the object is immersed in the plating solution. Even with this method, it is sufficient to apply it for a short time. Therefore, by simply adding an ultrasonic device, the occurrence of non-plated areas can be easily prevented without requiring any other process changes.

本発明の対象となる被めっき物の材質は特に限定されな
い０例えば、電子部品の場合は銅または銅合金が用いら
れる。The material of the object to be plated according to the present invention is not particularly limited; for example, in the case of electronic parts, copper or copper alloy is used.

被めっき物の微小な孔、凹部乃至間隙の寸法が直径で１
．０ｍｍ以下のものについても本発明の対称となる。The size of the minute hole, recess or gap in the object to be plated is 1 in diameter.
．． The present invention also applies to objects with a diameter of 0 mm or less.

なお、めフき層としては、例えば、Ｎｉめつき、Ｃｕめ
っき等があげられるがこれらに限定されるものではない
。Note that examples of the brushing layer include, but are not limited to, Ni plating, Cu plating, and the like.

［実施例］ （第１実施例） 純Ｃｕからなる試片（板厚１ｍｍｔ）に、第１図（ａ）
に示すように径１ｍｍφ、深さ０．５ｍｍの凹部を２０
個設け、また、他の試片には第１図（ｂ）に示すように
、１ｍｍφの貫通孔を２０個設け、それぞれ通常用いら
れるめっき前処理（トリクレン脱脂、アルカリ脱脂、電
解脱脂、酸洗）を行った後、表１に示す条件で、超音波
を印加した後、下記の条件でめっきを行なった。[Example] (First example) A specimen made of pure Cu (thickness: 1 mm) was prepared as shown in Fig. 1(a).
As shown in the figure, 20 recesses with a diameter of 1 mmφ and a depth of 0.5 mm are made.
In addition, as shown in Figure 1 (b), 20 through holes of 1 mm diameter were provided in the other specimens, and each sample was subjected to the commonly used plating pretreatments (triclene degreasing, alkaline degreasing, electrolytic degreasing, pickling). ), ultrasonic waves were applied under the conditions shown in Table 1, and plating was performed under the following conditions.

＜Ｎｉめっき〉 ・めっき液組成 Ｎ　ｉ　Ｓ　Ｏ４・６　Ｈ２０：　２４０　ｇ　／　Ｊ
ＩＮＬＣＩＬｚ　　・８Ｈｚ　Ｏ：　　４５ｇ／ｆＨ８
ＢＯｓ　　　　　　　：　　３０　ｇ／１１・めりき液
温度　　　５５℃ ・電流密度　　　　　２　Ａ　／　ｄ　ｍ　２・めっき
厚　　　　　　２μｍ ・超音波周波数　　　２８ｋＨｚ ・超音波印加出力　　５０ワツト ＜Ｃｕめっき〉 ・めっき液組成 ＣｕＳＯ４１５Ｈ２０：　２００ｇ／ｎＨｘ　Ｓ　Ｏ４
：　　５０　ｇ　／　’ＣＩＬ−：　　５０ｐｐｍ ・めっき液温度　　　３０℃ ・電流密度　　　　　２　Ａ　／　ｄ　ｍ　”・めっき
厚　　　　　２μｍ ・超音波周波数　　　２８ｋＨｚ ・超音波印加出力　　５０ワツト めりぎ後、孔、凹部乃至間隙における無めっき部の有無
を調査した。その結果を表１に示す。<Ni plating> ・Plating solution composition NiSO4・6 H20: 240 g/J
INLCILz ・8Hz O: 45g/fH8
BOs: 30 g/11・Plating solution temperature 55℃・Current density 2 A/dm2・Plating thickness 2μm・Ultrasonic frequency 28kHz・Ultrasonic application output 50W<Cu plating>・Plating solution composition CuSO415H20: 200g/ nHx SO4
: 50 g / 'CIL-: 50 ppm ・Plating solution temperature 30℃ ・Current density 2 A / dm'' ・Plating thickness 2μm ・Ultrasonic frequency 28kHz ・Ultrasonic applied output 50W After drilling, holes, recesses or gaps The presence or absence of unplated areas was investigated.The results are shown in Table 1.

表１においてＮ００１〜Ｎ０１４は本発明の実施例を示
し、Ｎｏ、５．Ｎｏ、６は従来例を示す。In Table 1, No. 001 to No. 014 indicate examples of the present invention, No. 5. No. 6 indicates a conventional example.

従来例（Ｎｏ、５．Ｎｏ、６）においては、ＮＬめっき
乃至Ｃｕめっき後に多数の無めっき部が認められたが、
実施例（Ｎｏ、１〜Ｎｏ、４）では、まったく無めっき
部は認められなかった。In the conventional examples (No. 5, No. 6), many unplated areas were observed after NL plating or Cu plating, but
In Examples (No. 1 to No. 4), no plating-free areas were observed at all.

（第２実施例） 本例では、゛凹部の寸法を径０．５ｍｍφ、深さ０．５
ｍｍ、貫通孔の寸法を径０．５ｍｍφと第１実施例より
より一層徴、小なものとした。(Second Example) In this example, the dimensions of the recess are 0.5 mm in diameter and 0.5 in depth.
The diameter of the through hole is 0.5 mm, which is much smaller than that of the first embodiment.

他の点は第１実施例と同様にして無めっき部の発生を調
査した。その結果を表２に示す。The other points were the same as in the first example, and the occurrence of unplated areas was investigated. The results are shown in Table 2.

表２において、Ｎｏ、７〜Ｎｏ、１０は実施例であり、
Ｎｏ、１１．Ｎｏ、１２は従来例である。In Table 2, No. 7 to No. 10 are Examples,
No, 11. No. 12 is a conventional example.

表２かられかるように、従来例（Ｎｏ、１１゜Ｎｏ、１
２）においては第１実施例の場合よりも無めっき部の数
ははるかに多かったが、実施例（Ｎｏ、７〜Ｎｏ、１０
）、においては第１実施例と同様に無めっき部は認めら
れなかった。As can be seen from Table 2, the conventional example (No, 11°No, 1
In 2), the number of unplated parts was much larger than in the first example, but in the example (No. 7 to No. 10)
), no unplated areas were observed as in the first example.

［発明の効果］ 本発明は、微小な孔、凹部乃至間隙を有する被めっき物
をめフきする場合に問題となる無めっき部の発生を防止
することができ、歩留および生産性を大幅に向上させる
ことができる。[Effects of the Invention] The present invention can prevent the occurrence of unplated areas, which is a problem when plating objects that have minute holes, recesses, or gaps, and can significantly improve yield and productivity. can be improved.

表２ めっき後の無めっき部の数（第２実施例）Table 2 Number of unplated areas after plating (2nd example)

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は試片の形状を示す側面図および正面図である。 孔および凹部の個数の合計２０個中の数第 （ａ） （ｂ） 二二斗１ｔ FIG. 1 is a side view and a front view showing the shape of the specimen. The total number of holes and recesses out of 20 (a) (b) 22 Dou 1t

Claims (1)

【特許請求の範囲】[Claims] 微小な孔、凹部乃至間隙を有する被めっき物をめっきす
る方法において、めっき液中で該被めっき物に超音波を
印加した後めっきを行なうことを特徴とするめっき方法
。A plating method for plating an object to be plated having minute holes, recesses or gaps, the plating method comprising applying ultrasonic waves to the object to be plated in a plating solution and then plating.