JP2010059547A - Electrolytic copper foil and method of electropolishing glossy surface of the electrolytic copper foil - Google Patents
Electrolytic copper foil and method of electropolishing glossy surface of the electrolytic copper foil Download PDFInfo
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Abstract
Description
本発明は、プリント配線板等に用いる電解銅箔及び電解銅箔光沢面（Ｓ面）の電解研磨方法に関する。特に光沢面に電解研磨を施し、表面粗さを低く抑えたまま、光沢面に微細な凹凸を形成し、レジストの密着性の向上及び光沢面で樹脂基板と密着させた場合の接着力の向上により、ロープロファイル化された、プリント基板用銅箔に好適な電解銅箔及びその製造方法に関する。 The present invention relates to an electrolytic copper foil used for a printed wiring board and the like, and an electrolytic polishing method for an electrolytic copper foil glossy surface (S surface). In particular, electrolytic polishing is applied to the glossy surface, and fine irregularities are formed on the glossy surface while keeping the surface roughness low, improving the adhesion of the resist and improving the adhesion when the glossy surface is in close contact with the resin substrate. The present invention relates to an electrolytic copper foil suitable for printed circuit board copper foil and a manufacturing method thereof.
近年、半導体装置や各種電子チップ部品等の、搭載部品の小型集積化技術の発達に伴い、これらを搭載するためのプリント配線板、特に高周波用基板に対して、配線のいっそうのファインパターン化及びロープロファイル化が求められている。
従来、粗化処理（被覆による凹凸の形成）し樹脂との接着性を向上させた電解銅箔が使用されていたが、この粗化処理のために銅箔のエッチング性が著しく損なわれ、高アスペクト比でのエッチングが困難となり、エッチング時にアンダーカットが発生し、十分なファインパターン化ができないという問題が生じた。
また、高周波用基板では、銅箔の表面粗さをできるだけ小さくすることが望まれている。このような銅箔のロープロファイル化は、高周波になるに従い銅箔の表面部分に電流が集中して流れる（この現象を表皮効果という）ようになり、銅箔の表面粗さが伝送損失に大きく影響すると考えられているためである。
In recent years, with the development of small integration technology for mounted components such as semiconductor devices and various electronic chip components, further fine patterning of wiring on printed wiring boards for mounting them, especially high frequency substrates, and Low profile is required.
Conventionally, an electrolytic copper foil that has been roughened (formation of irregularities by coating) and has improved adhesion to the resin has been used. Etching at an aspect ratio becomes difficult, undercut occurs during etching, and there is a problem that sufficient fine patterning cannot be achieved.
Moreover, in the high frequency board | substrate, it is desired to make the surface roughness of copper foil as small as possible. This low profile of copper foil causes current to concentrate and flow on the surface of the copper foil as the frequency increases (this phenomenon is called the skin effect), and the surface roughness of the copper foil increases transmission loss. This is because it is considered to be affected.
このため、エッチング時のアンダーカットの発生を抑制し、ファインパターン化及び高周波伝送損失低減の要求に対応するために、電解銅箔の粗化処理をより軽度にする、すなわちロープロファイル化(粗さの低減化)する提案がなされている。
また、一方では電解銅箔の光沢面に粗化処理（被覆による凹凸の形成）を行う提案もなされている。しかしながら、電解銅箔のこのようなロープロファイル化は工程を複雑にしコスト高になるという問題があり、また電解銅箔と樹脂との適度な接着強度が必ずしも得られないという問題がある。
このため、ハイレベルなファインパターン化及びロープロファイル化の要求はあるが、一方では所期の接着強度を維持することができず、配線が樹脂層から加工段階で剥離してしまうなどの問題が発生した。
For this reason, in order to suppress the occurrence of undercut during etching, and to meet the demand for fine patterning and reduction of high-frequency transmission loss, the roughening treatment of the electrolytic copper foil is made lighter, that is, low profile (roughness). Has been proposed.
On the other hand, a proposal has been made to perform roughening treatment (formation of irregularities by coating) on the glossy surface of the electrolytic copper foil. However, the low profile of the electrolytic copper foil has a problem that the process is complicated and the cost is high, and there is a problem that an appropriate adhesive strength between the electrolytic copper foil and the resin cannot always be obtained.
For this reason, there is a demand for high-level fine patterning and low profile, but on the other hand, the desired adhesive strength cannot be maintained, and there is a problem that the wiring peels off from the resin layer at the processing stage. Occurred.
このような問題の解決法として、表面が粗化処理されていない電解銅箔を使用し、その上に薄い亜鉛系金属層を形成、さらにその上にポリイミド系樹脂を形成する提案がなされている（例えば、特許文献１参照）。
また、アンダーカットを防止する目的で、電解銅箔上にリン含有ニッケルめっき層を形成する技術が提案されている（例えば、特許文献２参照）。しかし、この場合の電解銅箔の面は、粗面であることを要件としており、少なくともそれを許容している技術である。また、特許文献２の実施例は全て、電解銅箔の粗面にリン含有ニッケルめっき層を形成するものである。
銅箔の高度なファインパターン化のために要求される特性としては、このようなエッチングによるアンダーカットや樹脂との接着性だけの問題ではない。例えば、耐酸性、耐錫めっき液性、光沢度などにも優れていることが要求される。
しかし、従来は銅箔上に樹脂層を形成するプリント基板用銅箔、特に高周波基板用銅箔に対して、このような総合的な問題が検討されているとは言えず、上記の問題を解決できる好適な銅箔が見出されていないのが現状である。
As a solution to such a problem, a proposal has been made that an electrolytic copper foil whose surface is not roughened is used, a thin zinc-based metal layer is formed thereon, and a polyimide resin is further formed thereon. (For example, refer to Patent Document 1).
Moreover, the technique which forms a phosphorus containing nickel plating layer on electrolytic copper foil is proposed in order to prevent an undercut (for example, refer patent document 2). However, the surface of the electrolytic copper foil in this case is required to be a rough surface, and is a technique that at least allows it. Moreover, all the Examples of patent document 2 form a phosphorus containing nickel plating layer in the rough surface of an electrolytic copper foil.
The characteristics required for making a fine pattern of copper foil are not only problems such as undercut by etching and adhesion to resin. For example, it is required to be excellent in acid resistance, tin plating solution resistance, glossiness, and the like.
However, conventionally, it cannot be said that such comprehensive problems have been studied for copper foils for printed boards, particularly copper foils for high-frequency boards, in which a resin layer is formed on the copper foil. The present condition is that the suitable copper foil which can be solved is not found.
本発明は上記のような問題点に鑑みてなされたものであり、その目的とするところは、銅箔の光沢面とレジストとの密着性が優れ、また同光沢面で樹脂基板と密着させた場合の接着力を向上させることにより、ロープロファイル化されたプリント配線基板用銅箔を低コストで提供することにある。 The present invention has been made in view of the above-described problems, and the object of the present invention is excellent adhesion between the glossy surface of the copper foil and the resist, and the resin surface is brought into close contact with the same glossy surface. It is to provide a low profile copper foil for a printed wiring board at low cost by improving the adhesive strength in the case.
以上から、本発明は、１）電解銅箔の光沢面に、電解研磨によって形成された不規則かつ不定長の脈状起伏を備えていることを特徴とする電解銅箔、２）脈状起伏の高低差が２μｍ以下であることを特徴とする１記載の電解銅箔、３）電解銅箔の光沢面に、電解研磨によって形成された孔径２μｍ以下の多数の凹部を備えていることを特徴とする電解銅箔、４）電解銅箔の光沢面に、電解研磨によって形成された孔径２μｍ以下の多数の凹部を備えていることを特徴とする１又は２記載の電解銅箔、５）長尺の銅箔の、幅方向の光沢度が５０未満であり、長さ方向の光沢度が１００未満である電解研磨面された光沢面を備えていることを特徴とする電解銅箔、６）長尺の銅箔の、幅方向の光沢度が５０未満であり、長さ方向の光沢度が１００未満である電解研磨面された光沢面を備えていることを特徴とする１〜５いずれかに記載の電解銅箔、７）電解研磨面された光沢面に、Ｚｎ、Ｃｕ−Ｚｎ、Ｚｎ−Ｓｎ、Ｚｎ−Ｎｉ、Ｚｎ−Ｃｏ、Ｃｕ−Ｎｉ−Ｃｏ、Ｎｉ−Ｃｏ、Ｎｉ、Ｃｕ−Ｎｉ等の耐熱めっき層を備えていることを特徴とする１〜６のいずれかに記載の電解銅箔、８）前記耐熱めっき層の上に形成された有機系防錆剤による防錆処理層又はクロメート防錆処理層を備えていることを特徴とする７記載の電解銅箔、９）防錆処理層の上に、カップリング剤処理層を備えていることを特徴とする８記載の電解銅箔、を提供する。 As described above, the present invention provides 1) an electrolytic copper foil characterized in that the glossy surface of the electrolytic copper foil is provided with irregular and indefinite length undulations formed by electropolishing. 2) The undulations 2. The electrolytic copper foil according to 1 above, wherein the height difference is 2 μm or less, 3) The glossy surface of the electrolytic copper foil is provided with a large number of recesses having a pore diameter of 2 μm or less formed by electropolishing. 4) The electrolytic copper foil according to 1 or 2, characterized in that the glossy surface of the electrolytic copper foil is provided with a large number of recesses having a pore diameter of 2 μm or less formed by electropolishing. An electrolytic copper foil characterized by comprising an electropolished glossy surface having a widthwise glossiness of less than 50 and a lengthwise glossiness of less than 100, 6) The long copper foil has a glossiness in the width direction of less than 50 and a glossiness in the length direction of less than 100. The electrolytic copper foil according to any one of 1 to 5, characterized by comprising an electropolished glossy surface, 7) Zn, Cu-Zn, Zn-Sn on the electropolished glossy surface The electrolytic copper foil according to any one of 1 to 6, further comprising a heat-resistant plating layer such as Zn-Ni, Zn-Co, Cu-Ni-Co, Ni-Co, Ni, or Cu-Ni 8) An electrolytic copper foil according to 7, characterized by comprising an anticorrosive treatment layer or a chromate antirust treatment layer with an organic anticorrosive agent formed on the heat-resistant plating layer, and 9) an antirust treatment. 8. The electrolytic copper foil according to 8, wherein a coupling agent-treated layer is provided on the layer.
また、本発明は、１０）電解液として硫酸・硫酸銅浴を用い、電解銅箔の光沢面に電解研磨処理を行うことを特徴とする電解銅箔光沢面の電解研磨方法、１１）電解銅箔の粗面側にアノードを配置し光沢面側にカソードを配置して、電解処理を行うことにより、銅箔粗面に平滑めっき処理を行うとともに、銅箔光沢面に逆電解研磨処理を行うことを特徴とする１０）記載の電解銅箔光沢面の電解研磨方法、１２）前記光沢面への電解研磨処理の前に、硫酸・硫酸銅浴を用いて銅箔の粗化面に粗化めっき処理を行うことを特徴とする１０）又は１１）記載の電解銅箔光沢面の電解研磨方法、１３）電解銅箔をアノードとし、光沢面側にカソードを配置して、電解処理を行うことにより、銅箔光沢面側で逆電解研磨処理を行うことを特徴とする１０）記載の電解銅箔光沢面の電解研磨方法、１４）電解研磨後、研磨された光沢面に、Ｚｎ、Ｃｕ−Ｚｎ、Ｚｎ−Ｓｎ、Ｚｎ−Ｎｉ、Ｚｎ−Ｃｏ、Ｃｕ−Ｎｉ−Ｃｏ、Ｎｉ−Ｃｏ、Ｎｉ、Ｃｕ−Ｎｉ等の耐熱めっき処理を行うことを特徴とする１０〜１３のいずれかに記載の電解銅箔光沢面の電解研磨方法、１５）前記耐熱めっき処理に続いて、有機系防錆剤による防錆処理層又はクロメート防錆処理を行うことを特徴とする１４記載の電解銅箔光沢面の電解研磨方法、１６）防錆処理に続いて、カップリング剤処理を行うことを特徴とする１５記載の電解銅箔光沢面の電解研磨方法、１７）電解研磨による銅の溶解量が３〜１０ｇ／ｍ２であることを特徴とする１０〜１６のいずれかに記載の電解銅箔光沢面の電解研磨方法、を提供する。 The present invention also relates to 10) an electrolytic polishing method for an electrolytic copper foil glossy surface, characterized in that a sulfuric acid / copper sulfate bath is used as an electrolytic solution and the electrolytic copper foil glossy surface is subjected to an electrolytic polishing treatment. By placing the anode on the rough surface side of the foil and the cathode on the glossy surface side and performing electrolytic treatment, the copper foil rough surface is subjected to smooth plating treatment and the copper foil glossy surface is subjected to reverse electrolytic polishing treatment. 10) Electrolytic polishing method for glossy surface of electrolytic copper foil according to 10), 12) Roughening to roughened surface of copper foil using sulfuric acid / copper sulfate bath before electrolytic polishing treatment to glossy surface Electrolytic polishing method for electrolytic copper foil glossy surface as described in 10) or 11), wherein plating treatment is performed, 13) Electrolytic treatment is performed with electrolytic copper foil as anode and cathode on glossy surface side 1 is characterized in that the reverse electrolytic polishing treatment is performed on the copper foil glossy surface side. 14) Electropolishing method for electrolytic copper foil glossy surface, 14) After electropolishing, on the polished glossy surface, Zn, Cu—Zn, Zn—Sn, Zn—Ni, Zn—Co, Cu—Ni—Co, Electrolytic polishing method for electrolytic copper foil glossy surface according to any one of 10 to 13, characterized by performing heat-resistant plating treatment of Ni-Co, Ni, Cu-Ni, etc., 15) Following the heat-resistant plating treatment, 14. The electrolytic polishing method for an electrolytic copper foil glossy surface according to 14, characterized in that an anticorrosive treatment layer or chromate anticorrosion treatment with an organic anticorrosive agent is performed, 16) a coupling agent treatment is performed following the antirust treatment 15 electrolytic polishing method of the electrodeposited copper foil shiny side, wherein the, 17) the amount of dissolution of copper by electrolytic polishing as claimed in any one of 10-16, which is a 3 to 10 g / m 2 An electrolytic polishing method for an electrolytic copper foil glossy surface is provided.
本発明は、銅箔の光沢面とレジストとの密着性又は同光沢面と樹脂基板と密着させた場合の接着力を向上させることが可能であり、またピール強度が高く、良好なエッチング性と適度な光沢度を備え、さらに配線のファインパターン化及びロープロファイル化が可能であるという優れた効果を有する。 The present invention can improve the adhesion between the glossy surface of the copper foil and the resist, or the adhesion when the glossy surface is in close contact with the resin substrate, and has high peel strength and good etching properties. It has an excellent effect that it has an appropriate glossiness and can be finely patterned and low-profiled.
一般に、電解銅箔は、回転する金属製陰極ドラムと、その陰極ドラムのほぼ下方半分の位置に配置した該陰極ドラムの周囲を囲む不溶性金属アノード（陽極）を使用し、前記陰極ドラムとアノードとの間に銅電解液を流動させかつこれらの間に電位を与えて陰極ドラム上に銅を電着させ、所定厚みになったところで、該陰極ドラムから電着した銅を剥がして連続的に銅箔が製造されている。
このようにして製造される電解銅箔は、ドラム側に接触していた光沢面（シャイニー面又はＳ面）とその反対側の微小な凹凸のある粗面（マット面又はＭ面）を有する。
本発明は、光沢面に電解による研磨を行うことが大きな特徴である。これによって、電解銅箔の光沢面に微細な凹凸が形成される。この凹凸は不規則かつ不定長の脈状起伏を呈しており、後述する図３〜図９に示すように（なお、図３のみ逆電解処理を行っていない生の光沢面を示す。）、その様相はさんご礁の表面に類似している。この脈状起伏の高低差は２μｍ以下、特に１μｍ以下であり、無数の起伏を形成している。
In general, the electrolytic copper foil uses a rotating metal cathode drum and an insoluble metal anode (anode) surrounding the cathode drum, which is disposed at a position approximately half below the cathode drum. A copper electrolyte is allowed to flow between the electrodes, and an electric potential is applied between them to electrodeposit copper on the cathode drum. When a predetermined thickness is reached, the electrodeposited copper is peeled off from the cathode drum and the copper is continuously removed. A foil is being manufactured.
The electrolytic copper foil produced in this way has a glossy surface (shiny surface or S surface) that has been in contact with the drum side and a rough surface (matt surface or M surface) with minute irregularities on the opposite side.
A major feature of the present invention is that the glossy surface is polished by electrolysis. Thereby, fine irregularities are formed on the glossy surface of the electrolytic copper foil. The irregularities have irregular and indefinite length undulations, and as shown in FIGS. 3 to 9 described later (only FIG. 3 shows a raw glossy surface not subjected to reverse electrolysis). Its appearance is similar to the surface of a coral reef. The difference in level of the undulations is 2 μm or less, particularly 1 μm or less, forming innumerable undulations.
また、このような電解銅箔の光沢面に形成された電解研磨面は、平均孔径が２μｍ以下、特に１μｍ以下の多数の凹部が形成される場合がある。また、上記脈状起伏とこの凹部とが混在している場合もある。いずれも電解銅箔の光沢面に形成された電解研磨による結果である。
このようにして形成された電解銅箔光沢面の研磨面の光沢度は、幅方向と長さ方向で相違が見られ、無処理（研磨していない）光沢面に比べ、いずれも光沢度は低下する。本発明においては、幅方向の光沢度を５０未満とし、長さ方向の光沢度が１００未満とする。これによって、特に高周波基板用銅箔に必要なピール強度を得ることができる。
In addition, the electrolytic polishing surface formed on the glossy surface of such an electrolytic copper foil may have a large number of recesses having an average pore diameter of 2 μm or less, particularly 1 μm or less. In some cases, the undulations and the recesses are mixed. All are the results of electrolytic polishing formed on the glossy surface of the electrolytic copper foil.
The glossiness of the polished surface of the electrolytic copper foil glossy surface formed in this way is different between the width direction and the lengthwise direction, and the glossiness of both is compared to the untreated (unpolished) glossy surface. descend. In the present invention, the glossiness in the width direction is less than 50, and the glossiness in the length direction is less than 100. As a result, the peel strength necessary for the copper foil for high-frequency substrates can be obtained.
この光沢面の微小な凹凸は、電解液として硫酸・硫酸銅浴を用い、電解銅箔の光沢面に電解研磨処理を行うことによって形成できる。
図１に逆電解装置の概念説明図を示す。図１において、電解銅箔１の粗面（Ｍ面）側２にアノード３を配置し、光沢面（Ｓ面）側４にカソード５を配置して、電解処理を行うことにより、銅箔粗面２に平滑めっき処理を行うとともに、銅箔光沢面４に逆電解研磨処理を行うことによって形成できる。符号６はアッパーロール、符号７はシンカーロールである。
The minute unevenness on the glossy surface can be formed by performing an electrolytic polishing treatment on the glossy surface of the electrolytic copper foil using a sulfuric acid / copper sulfate bath as an electrolytic solution.
FIG. 1 is a conceptual explanatory diagram of a reverse electrolysis apparatus. In FIG. 1, the electrolytic copper foil 1 has an anode 3 disposed on the rough surface (M surface) side 2 and a cathode 5 disposed on the glossy surface (S surface) side 4 to perform the electrolytic treatment. It can be formed by performing a smooth plating process on the surface 2 and performing a reverse electrolytic polishing process on the copper foil glossy surface 4. Reference numeral 6 denotes an upper roll, and reference numeral 7 denotes a sinker roll.
また、粗化面（マット面）に対しては、光沢面への電解研磨処理の前に、硫酸・硫酸銅浴を用いて銅箔の粗化面に粗化めっき処理を行うことができる。また、電解銅箔をアノードとし、光沢面側にカソードを配置して、電解処理を行うことにより、銅箔光沢面側で逆電解研磨処理を行うことによっても、電解銅箔光沢面の電解研磨を行うことができる。 For the roughened surface (matte surface), the roughened surface of the copper foil can be subjected to roughening plating treatment using a sulfuric acid / copper sulfate bath before the electrolytic polishing treatment for the glossy surface. Electrolytic polishing of the electrolytic copper foil glossy surface can also be performed by using the electrolytic copper foil as the anode and performing the electrolytic treatment by arranging the cathode on the glossy surface side and performing the electrolytic treatment on the copper foil glossy surface side. It can be performed.
図２は生の光沢面（電子顕微鏡写真（×３０００）、以下同様）を示す。表面粗さＲｚ１．４μｍであり、不規則かつ不定長の脈状起伏はなく、凹部も一切見られず、滑らかな表面を有している。
図３は逆電解により２．０ｇ／ｍ２を溶解させたものであり、溶解量は小さいが、不規則かつ不定長の脈状起伏が発生し、無数の凹部も見られるようになる。
図４〜図９は、逆電解により、さらに３．０ｇ／ｍ２、４．０ｇ／ｍ２、５．０ｇ／ｍ２、６．０ｇ／ｍ２、７．０ｇ／ｍ２、８．０ｇ／ｍ２を溶解させた光沢面を示す。溶解量が多くなるにつれて、不規則かつ不定長の脈状起伏が顕著になり、無数の凹部も深くなっているのが分かる。
FIG. 2 shows a raw glossy surface (electron micrograph (× 3000), the same applies hereinafter). The surface roughness is Rz 1.4 μm, there are no irregular undulations, no undulations, no recesses, and a smooth surface.
FIG. 3 is obtained by dissolving 2.0 g / m 2 by reverse electrolysis. Although the dissolution amount is small, irregular and indefinite length undulations occur, and innumerable recesses are also seen.
4 to FIG. 9 show that 3.0 g / m 2 , 4.0 g / m 2 , 5.0 g / m 2 , 6.0 g / m 2 , 7.0 g / m 2 , 8.0 g by reverse electrolysis. A glossy surface in which / m 2 is dissolved is shown. It can be seen that as the amount of dissolution increases, irregular and indefinite length undulations become more prominent and innumerable recesses become deeper.
ここで特徴的なのは、光沢面の表面粗さＲｚ１．４μｍであるのに対して、逆電解した図３〜図９についてはＲｚ１．４２〜１．５３μｍの範囲にあり、殆ど差異がない。また、溶解量との相関も見られない。したがって、逆電解した光沢面は表面粗さによっては区別できないことを意味する。
しかし、後述する実施例及び比較例に示すように、光沢度によって明瞭な差異がある。詳細は後述する。
What is characteristic here is the surface roughness Rz of 1.4 μm for the glossy surface, while FIGS. 3 to 9 subjected to reverse electrolysis are in the range of Rz 1.42 to 1.53 μm, and there is almost no difference. In addition, no correlation with the dissolved amount is observed. Therefore, it means that the reversely electrolyzed glossy surface cannot be distinguished depending on the surface roughness.
However, as shown in Examples and Comparative Examples described later, there is a clear difference depending on the glossiness. Details will be described later.
電解研磨後、研磨された光沢面に、Ｚｎ、Ｃｕ−Ｚｎ、Ｚｎ−Ｓｎ、Ｚｎ−Ｎｉ、Ｚｎ−Ｃｏ、Ｃｕ−Ｎｉ−Ｃｏ、Ｎｉ−Ｃｏ、Ｎｉ、Ｃｕ−Ｎｉ等の耐熱めっき処理を行い、耐熱めっき層を形成することができる。これらの耐熱めっきは公知のめっきを適用することができる。
また、前記耐熱めっき処理に続いて、有機系防錆剤による防錆処理層又はクロメート防錆処理、さらにはこの防錆処理に続いて、シランカップリング剤等によるカップリング剤処理を行うこともできる。このカップリング剤処理によって、常態ピール強度をさらに向上させることができる。防錆処理及びカップリング剤処理も公知の処理を適用することができ、その材料に特に制限されない。
電解研磨による銅の溶解量を３〜１０ｇ／ｍ２とすることにより、常態ピール強度を向上させることができる。電解銅箔の光沢面に逆電解研磨し、さらにシランカップリング剤処理した銅箔のピール強度と、銅溶解量との関係を図１０に示す。銅溶解量が増大する、すなわち逆電解研磨をより強く行うことにより、光沢面の凹凸は大きくなり銅箔のピール強度が高くなる。
After electrolytic polishing, the polished glossy surface is subjected to heat-resistant plating treatment such as Zn, Cu—Zn, Zn—Sn, Zn—Ni, Zn—Co, Cu—Ni—Co, Ni—Co, Ni, and Cu—Ni. And a heat-resistant plating layer can be formed. Known heat-resistant plating can be applied to these heat-resistant platings.
Further, following the heat-resistant plating treatment, a rust-proofing layer or chromate rust-proofing treatment with an organic rust-proofing agent, and further, following this rust-proofing treatment, a coupling agent treatment with a silane coupling agent or the like may be performed. it can. This coupling agent treatment can further improve the normal peel strength. A known treatment can be applied to the rust prevention treatment and the coupling agent treatment, and the material is not particularly limited.
The normal peel strength can be improved by setting the amount of copper dissolved by electropolishing to 3 to 10 g / m 2 . FIG. 10 shows the relationship between the peel strength of the copper foil subjected to reverse electrolytic polishing on the glossy surface of the electrolytic copper foil and further treated with the silane coupling agent, and the amount of copper dissolved. By increasing the amount of copper dissolved, that is, by performing reverse electropolishing more strongly, the unevenness of the glossy surface increases and the peel strength of the copper foil increases.
このような光沢面の逆電解研磨による微小な凹凸は通常の表面粗さでは、大きな変化は見られず、十点平均粗さ（Ｒｚ）で１．４〜１．６（μｍ）の範囲にある。このような微小な光沢面の凹凸は、高いエッチング精度を得ることができる。すなわちエッチング精度を上げるためには、原箔の表面粗さをより小さくすることが重要である。光沢面の粗化処理は不要である。
このようにして製造された本発明の電解銅箔は連続的にコイルに巻かれ、その後、さらに電気化学的若しくは化学的又は樹脂等の表面処理又は被覆処理（コーティング）を施してプリント配線板等に使用することができる。
Such irregularities caused by reverse electrolytic polishing of the glossy surface do not show a large change in the normal surface roughness, and the ten-point average roughness (Rz) is in the range of 1.4 to 1.6 (μm). is there. Such minute unevenness on the glossy surface can provide high etching accuracy. That is, in order to increase the etching accuracy, it is important to reduce the surface roughness of the original foil. There is no need to roughen the glossy surface.
The electrolytic copper foil of the present invention thus produced is continuously wound around a coil, and then subjected to a surface treatment or coating treatment (coating) such as electrochemical or chemical or resin to produce a printed wiring board or the like. Can be used for
これによって、銅箔の光沢面ではあるが、レジスト又は高周波用途向け樹脂層との間の接着強度が優れており、また同時に耐酸性及び耐錫めっき液性を備え、さらにピール強度が高く、良好なエッチング性と適度な光沢度を備え、さらに配線のファインパターン化が可能であるという総合的な優れた効果を保有させることができる。
銅箔の厚みは、特に限定する必要はなく、用途に応じた厚みの銅箔に適用できる。例えば高密度配線として使用するためには１８μｍ以下、さらには３〜１２μｍの厚さのものが要求されているが、本発明の銅箔処理は、このような厚さに制限なく適用できる。また、さらに極薄箔又は１８μｍ以上の、例えば３５μｍ程度の厚い銅箔においても同様に適用できる。
また、その他の表面処理として、必要に応じてクロム系金属、亜鉛系金属、有機系の防錆処理を施すことができる。また、シランカップリング剤等のカップリング剤処理を施すこともできる。これらは、プリント配線基板の銅箔の用途に応じて適宜選択されるものであり、本発明はこれらを全て包含する。
Although it is a glossy surface of copper foil, it has excellent adhesion strength between the resist and the resin layer for high frequency applications, and at the same time has acid resistance and tin plating solution resistance, and also has high peel strength and good It has excellent etching properties and moderate glossiness, and can have a comprehensive excellent effect that a fine pattern of wiring is possible.
The thickness of the copper foil is not particularly limited, and can be applied to a copper foil having a thickness according to the use. For example, in order to be used as a high-density wiring, a thickness of 18 μm or less, and further a thickness of 3 to 12 μm is required, but the copper foil treatment of the present invention can be applied to such a thickness without limitation. Further, the present invention can be similarly applied to an extremely thin foil or a thick copper foil of 18 μm or more, for example, about 35 μm.
Further, as other surface treatments, chromium-based metal, zinc-based metal, and organic rust preventive treatment can be performed as necessary. Moreover, coupling agent processing, such as a silane coupling agent, can also be performed. These are suitably selected according to the use of the copper foil of a printed wiring board, and this invention includes all these.
樹脂層を形成する手段としては、特に制限されるものではないが、例えば原料としてポリイミド樹脂層であるポリアミック酸ワニス（芳香族ジアミン類と芳香族酸二無水物とを溶液状態で付加重合させて得られるポリアミック酸を含有する混合物）を使用することができる。
このポリアミック酸ワニスを、本発明の電解銅箔光沢面上に塗布し、さらに乾燥してポリイミド前駆体層としてのポリアミック酸層を形成する。得られたポリアミック酸層を、窒素等の不活性雰囲気下で３００°Ｃ〜４００°Ｃに加熱してイミド化し、ポリイミド系樹脂層を形成する。
ポリイミド系樹脂層の厚みは特に限定されないが、通常１０〜５０μｍとする。また、ポリアミック酸ワニスには、必要に応じて従来公知の添加剤を配合してもよい。このようにして得られるプリント基板においては、本発明の電解銅箔とポリイミド系樹脂層との接着強度が良好なものとなる。
The means for forming the resin layer is not particularly limited. For example, a polyamic acid varnish that is a polyimide resin layer as a raw material (addition polymerization of an aromatic diamine and an aromatic dianhydride in a solution state is performed. The resulting mixture containing polyamic acid can be used.
This polyamic acid varnish is applied onto the glossy surface of the electrolytic copper foil of the present invention and further dried to form a polyamic acid layer as a polyimide precursor layer. The obtained polyamic acid layer is imidized by heating to 300 ° C. to 400 ° C. under an inert atmosphere such as nitrogen to form a polyimide resin layer.
Although the thickness of a polyimide-type resin layer is not specifically limited, Usually, you may be 10-50 micrometers. Moreover, you may mix | blend a conventionally well-known additive with a polyamic-acid varnish as needed. In the printed circuit board thus obtained, the adhesive strength between the electrolytic copper foil of the present invention and the polyimide resin layer is good.
次に、実施例に基づいて説明する。なお、本実施例は好適な一例を示すもので、本発明はこれらの実施例に限定されるものではない。したがって、本発明の技術思想に含まれる変形、他の実施例又は態様は、全て本発明に含まれる。
なお、本発明との対比のために、比較例を掲載した。
Next, a description will be given based on examples. In addition, a present Example shows a suitable example, This invention is not limited to these Examples. Accordingly, all modifications and other examples or aspects included in the technical idea of the present invention are included in the present invention.
In addition, the comparative example was published for contrast with this invention.
（実施例１〜６）
回転ドラムを陰極として、電気分解反応により連続的に銅をドラムに電着させ、厚さ３５μｍの銅箔を製造した。
この銅箔の光沢面（Ｓ面）側にカソードを配置し、銅箔をアノードとして、直流による電解処理を施すことにより、銅箔光沢面（Ｓ面）側で逆電解研磨処理を行い、銅を３〜８ｇ／ｍ２を溶解させた。
銅箔幅方向の光沢度は１３〜４０、銅箔長さ方向の光沢度は２０〜９４であった。
次いで、耐熱処理層として黄銅めっき層を形成した。この時の亜鉛の付着量は４５００μｇ／ｄｍ２であった。引続き直ちに、電解亜鉛−クロム処理により防錆層を形成し、さらに０．４％ビニルトリエトキシシラン水溶液をスプレー塗布、乾燥し、シランカップリング剤処理層を形成した。
(Examples 1-6)
Using the rotating drum as a cathode, copper was continuously electrodeposited on the drum by an electrolysis reaction to produce a 35 μm thick copper foil.
A cathode is disposed on the glossy surface (S surface) side of this copper foil, and by performing electrolytic treatment with direct current using the copper foil as an anode, a reverse electrolytic polishing treatment is performed on the copper foil glossy surface (S surface) side. 3 to 8 g / m 2 was dissolved.
The glossiness in the copper foil width direction was 13 to 40, and the glossiness in the copper foil length direction was 20 to 94.
Next, a brass plating layer was formed as a heat-resistant treatment layer. The adhesion amount of zinc at this time was 4500 μg / dm 2 . Immediately thereafter, an anticorrosive layer was formed by electrolytic zinc-chromium treatment, and a 0.4% vinyltriethoxysilane aqueous solution was spray-coated and dried to form a silane coupling agent-treated layer.
（比較例１、２）
比較例１及び２は、実施例１において、次のように条件を変更した以外は、実施例１と同様にして銅箔を作製した。
比較例１：銅箔Ｓ面側逆電解研磨処理なし（銅溶解量０ｇ／ｍ２）
比較例２：銅箔Ｓ面側逆電解研磨処理あり（銅溶解量２ｇ／ｍ２）
(Comparative Examples 1 and 2)
In Comparative Examples 1 and 2, a copper foil was produced in the same manner as in Example 1 except that the conditions in Example 1 were changed as follows.
Comparative Example 1: No copper foil S surface side reverse electrolytic polishing treatment (copper dissolution amount 0 g / m 2 )
Comparative Example 2: With copper foil S surface side reverse electrolytic polishing treatment (copper dissolution amount 2 g / m 2 )
（ドライフィルム密着性試験）
上記のように表面処理された銅箔を、ポリフェニレンエーテルを主成分として含浸したガラス繊維基材と加熱プレスし、銅張積層板を作製した。この銅張積層板に、バフ研磨やソフトエッチング等の前処理を施さずにドライフィルムをラミネートし、露光、現像して、密着性を目視で評価した。この結果を表１に示す。
比較例の場合、バフ研磨やソフトエッチング等の前処理を施さないと密着不良がでる場合も見られたが、実施例は全て非常に良好なドライフィルム密着性を有していた。
(Dry film adhesion test)
The copper foil surface-treated as described above was hot-pressed with a glass fiber substrate impregnated with polyphenylene ether as a main component to produce a copper-clad laminate. The copper-clad laminate was laminated with a dry film without pretreatment such as buffing or soft etching, exposed, developed, and visually evaluated for adhesion. The results are shown in Table 1.
In the case of the comparative example, there was a case where adhesion failure occurred unless pretreatment such as buffing or soft etching was performed, but all the examples had very good dry film adhesion.
（接着性試験）
上記のように表面処理された銅箔を、ポリフェニレンエーテルを主成分として含浸したガラス繊維基材と加熱プレスし、銅張積層板を作製した。この銅張積層板をＪＩＳ Ｃ ６４８１に規定する方法で常態ピール強度を測定した。
この結果を同様に表１に示す。比較例に比べ、実施例では絶縁樹脂との密着性に優れていることが確認された。
図１０に、高周波用基板（シランカップリング剤処理）とＦＲ−４（シランカップリング剤処理なし）の逆電解銅溶解量とピール強度の関係を示すグラフを、図１１に、ＦＲ−４（シランカップリング剤処理）の逆電解銅溶解量とピール強度の関係を示すグラフ掲載した。
(Adhesion test)
The copper foil surface-treated as described above was hot-pressed with a glass fiber substrate impregnated with polyphenylene ether as a main component to produce a copper-clad laminate. The normal peel strength of this copper clad laminate was measured by the method specified in JIS C 6481.
The results are also shown in Table 1. Compared to the comparative example, it was confirmed that the example has excellent adhesion to the insulating resin.
FIG. 10 is a graph showing the relationship between the amount of reverse electrolytic copper dissolved in the high frequency substrate (treated with the silane coupling agent) and FR-4 (without silane coupling agent treatment) and the peel strength, and FIG. A graph showing the relationship between the amount of dissolved reverse electrolytic copper and the peel strength of the silane coupling agent treatment) is shown.
上記表１、図１０、図１１に示すように、本発明の実施例については、いずれも非常に良好なレジスト（ドライフィルム）密着性を示した。これに対して、比較例１、２ではバフ研磨やソフトエッチングを施さないと、密着不良となる場合があった。
また、樹脂との密着試験では、常態ピール強度が０．７６〜０．８９ｋｇ／ｃｍといずれも良好な値を示した。これに対し、比較例では０．５５、０．５９ｋｇ／ｃｍと０．６ｋｇ／ｃｍ未満であった。このようなケースについては、回路剥離を起こす可能性が高くなり好ましくない。
一方、粗さが増加するとエッチング特性に悪影響を与え、銅箔エッチング後の樹脂表面の平滑性を損なうことがあるが、上記のように、光沢面の表面粗さＲｚと逆電解したＲｚに殆ど差異がない。これは粗さによるエッチング特性に影響を与えないことを意味し、良好なエッチング特性を有していることも明らかである。
As shown in Table 1, FIG. 10, and FIG. 11, all of the examples of the present invention exhibited very good resist (dry film) adhesion. On the other hand, in Comparative Examples 1 and 2, if buffing or soft etching is not performed, adhesion failure may occur.
In the adhesion test with the resin, the normal peel strength was 0.76 to 0.89 kg / cm, both of which were good values. On the other hand, in the comparative example, it was 0.55, 0.59 kg / cm and less than 0.6 kg / cm. Such a case is not preferable because the possibility of circuit peeling increases.
On the other hand, when the roughness is increased, the etching characteristics are adversely affected, and the smoothness of the resin surface after the copper foil etching may be impaired. As described above, the surface roughness Rz of the glossy surface is almost equal to the Rz that is reversely electrolyzed. There is no difference. This means that the etching characteristics due to roughness are not affected, and it is clear that the etching characteristics are good.
本発明は、銅箔の光沢面とレジストとの密着性又は同光沢面と樹脂基板と密着させた場合の接着力を向上させることが可能であり、またピール強度が高く、良好なエッチング性と適度な光沢度を備え、ロープロファイル化されたプリント配線基板に好適な銅箔を提供できる。 The present invention can improve the adhesion between the glossy surface of the copper foil and the resist, or the adhesion when the glossy surface is in close contact with the resin substrate, and has high peel strength and good etching properties. A copper foil suitable for a low-profile printed wiring board having an appropriate glossiness can be provided.
１ 電解銅箔
２ 粗面（Ｍ面）側
３ アノード
４ 光沢面（Ｓ面）側
５ カソード
６ アッパーロール
７ シンカーロール
DESCRIPTION OF SYMBOLS 1 Electrolytic copper foil 2 Rough surface (M surface) side 3 Anode 4 Glossy surface (S surface) side 5 Cathode 6 Upper roll 7 Sinker roll
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08120499A (en) * | 1994-10-20 | 1996-05-14 | Nikko Gould Foil Kk | Surface treatment of copper foil for printed circuit by in-liquid current collection |
| JPH08158100A (en) * | 1994-10-06 | 1996-06-18 | Furukawa Circuit Foil Kk | Roughening of copper foil surface |
| JPH10168596A (en) * | 1996-12-10 | 1998-06-23 | Fukuda Metal Foil & Powder Co Ltd | Surface treatment of copper foil |
| JPH10310881A (en) * | 1997-05-12 | 1998-11-24 | Toppan Printing Co Ltd | Method for etching copper-base metallic material |
-
2009
- 2009-10-01 JP JP2009229801A patent/JP2010059547A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08158100A (en) * | 1994-10-06 | 1996-06-18 | Furukawa Circuit Foil Kk | Roughening of copper foil surface |
| JPH08120499A (en) * | 1994-10-20 | 1996-05-14 | Nikko Gould Foil Kk | Surface treatment of copper foil for printed circuit by in-liquid current collection |
| JPH10168596A (en) * | 1996-12-10 | 1998-06-23 | Fukuda Metal Foil & Powder Co Ltd | Surface treatment of copper foil |
| JPH10310881A (en) * | 1997-05-12 | 1998-11-24 | Toppan Printing Co Ltd | Method for etching copper-base metallic material |
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