JP5940010B2 - Surface roughening copper foil, method for producing the same, and circuit board - Google Patents
Surface roughening copper foil, method for producing the same, and circuit board Download PDFInfo
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Description
本発明は、耐屈曲性、可撓性、耐熱性に優れた表面粗化処理銅箔に関するもので、特に耐熱性、可撓性に優れた回路基板、例えばフレキシブルプリント配線板（以下ＦＰＣと略す）用に適した表面粗化処理銅箔に関するものである。 The present invention relates to a surface-roughened copper foil having excellent bending resistance, flexibility, and heat resistance. Particularly, the present invention relates to a circuit board excellent in heat resistance and flexibility, such as a flexible printed wiring board (hereinafter abbreviated as FPC). It relates to a surface roughened copper foil suitable for use.
最近のＦＰＣは通常２種類に分けられる。一つは、絶縁フィルム（ポリイミド、ポリエステル等）に銅箔を接着樹脂で張り付け、エッチング処理してパターンを施したものである。このタイプのＦＰＣを通常三層ＦＰＣと呼んでいる。これに対してもう一つのタイプは、接着剤を使用せずに絶縁フィルム（ポリイミド、液晶ポリマー等）と直接銅箔を積層したＦＰＣである。これを通常二層ＦＰＣと呼んでいる。
ＦＰＣの主な用途は、液晶ディスプレイ、プラズマディスプレイ等のフラットパネルディスプレイ用、或いはカメラ、ＡＶ機器、パソコン、コンピューター端末機器、ＨＤＤ、携帯電話、カーエレクトロニクス機器等の内部配線用である。これらの配線は機器に折り曲げて装着し、或いは繰り返して曲げられるような箇所に使用されるため、ＦＰＣ用銅箔に対する要求特性として、屈曲性に優れていることが一つの重要な特性である。
Recent FPCs are usually divided into two types. One is a pattern in which a copper foil is attached to an insulating film (polyimide, polyester, etc.) with an adhesive resin and etched to give a pattern. This type of FPC is usually called a three-layer FPC. On the other hand, another type is an FPC in which an insulating film (polyimide, liquid crystal polymer, etc.) and a copper foil are directly laminated without using an adhesive. This is usually called a two-layer FPC.
The main applications of FPC are for flat panel displays such as liquid crystal displays and plasma displays, or for internal wiring of cameras, AV equipment, personal computers, computer terminal equipment, HDDs, mobile phones, car electronics equipment, and the like. Since these wirings are used in places where they are bent and attached to equipment or repeatedly bent, one of the important characteristics of FPC copper foil is that it is excellent in flexibility.
ＦＰＣ用銅箔には大きく分けて２種類ある。一つは鋳造により製造した銅の鋳塊に圧延加工を施して箔状とした圧延銅箔である。もう一つは電解銅箔である。
これらの未処理銅箔には表面処理が施されている。
There are roughly two types of copper foil for FPC. One is a rolled copper foil obtained by rolling a copper ingot produced by casting into a foil shape. Another is electrolytic copper foil.
These untreated copper foils are surface treated.
ＦＰＣ用銅箔には上述したように屈曲性が要求されるため、従来は圧延銅箔の使用割合が高かった。圧延銅箔はＦＰＣ製造時、銅箔とポリイミドの張り合わせ工程で加熱される１２０〜１６０℃という比較的低温で焼鈍されて軟化が起こり、屈曲性や伸びが大きくなるという特徴を有するからである。
しかし圧延銅箔は電解銅箔に比較して高価であり、特に１２μｍ、９μｍといった薄物になるほど飛躍的にコストが上昇する。これは薄物を作る場合、厚い銅箔を何回にも渡って圧延を繰り返して製造するためである。また圧延で製造される銅箔の幅は通常６００ｍｍ程度と狭く、ＦＰＣ製造時の生産性が悪いという欠点がある。
Since the copper foil for FPC is required to be flexible as described above, conventionally, the use ratio of the rolled copper foil has been high. This is because the rolled copper foil is characterized in that it is annealed at a relatively low temperature of 120 to 160 ° C. that is heated in the bonding process of the copper foil and the polyimide during FPC production, softens, and has high flexibility and elongation.
However, the rolled copper foil is more expensive than the electrolytic copper foil, and in particular, the cost increases dramatically as the thickness becomes 12 μm or 9 μm. This is because when making a thin object, a thick copper foil is repeatedly rolled over and over. Moreover, the width of the copper foil manufactured by rolling is as narrow as about 600 mm normally, and there exists a fault that productivity at the time of FPC manufacture is bad.
これに対して、電解銅箔は圧延銅箔に比べて安価であり、通常１，０００ｍｍ以上の幅の銅箔を製造することが可能であり、ＦＰＣ製造時の生産性に優れる利点がある一方、従来の製造方法で製造された電解銅箔は、圧延銅箔に比べ２００℃以上に加熱しても焼鈍、軟化せず、屈曲性が悪く、ＦＰＣ用の銅箔としては使用用途が限られていた。
このような電解銅箔の欠点を解消し、屈曲性に優れた銅箔の開発がなされ（特許文献1参照）、電解銅箔の屈曲性は圧延銅箔と同等レベルまで引き上げられた。
On the other hand, the electrolytic copper foil is cheaper than the rolled copper foil, and it is possible to produce a copper foil having a width of 1,000 mm or more, which has an advantage of excellent productivity at the time of FPC production. The electrolytic copper foil produced by the conventional production method is not annealed or softened even when heated to 200 ° C. or higher as compared with the rolled copper foil, has poor flexibility, and has limited use as a copper foil for FPC. It was.
Development of a copper foil excellent in bendability has been made to eliminate such drawbacks of the electrolytic copper foil (see Patent Document 1), and the bendability of the electrolytic copper foil has been raised to a level equivalent to that of the rolled copper foil.
一方、近年の電子機器の技術革新は目覚しいものがあり、機器のコンパクト化が進む一方で、これらの機器に用いられるＦＰＣも、それに対応するため、多ピン化、ファインピッチ化が急速に進んでおり、そのような要望を満足させると共にその信頼性を向上させるために、より屈曲寿命の長い銅箔が要求されてきている。 On the other hand, there are remarkable technological innovations in electronic devices in recent years, and while devices are becoming more compact, FPCs used in these devices are also rapidly increasing in number of pins and in fine pitches. In order to satisfy such a demand and improve the reliability, a copper foil having a longer bending life has been required.
上述したようにＦＰＣに要求される特性、あるいは絶縁フィルム（ポリイミド、ポリエステル、液晶ポリマー等）上に、銅箔を張り付けた銅張積層板（以下、ＣＣＬと略記することがある）に回路を形成するプリント配線板に要求される特性は、耐屈曲性、可撓性、耐熱性に優れた表面粗化処理銅箔である。 As described above, a circuit is formed on a copper clad laminate (hereinafter abbreviated as CCL) in which copper foil is pasted on the characteristics required for FPC or on an insulating film (polyimide, polyester, liquid crystal polymer, etc.) The characteristic required for the printed wiring board to be is a surface-roughened copper foil excellent in bending resistance, flexibility and heat resistance.
ＦＰＣに使用する圧延銅箔、電解銅箔は共に、絶縁フィルムとの接着力を上げるために銅箔の少なくともフィルムと接着する面に銅粒をめっきにより付着する粗化処理を施し、もう一方の面は防錆或いは耐熱変色を抑える目的の亜鉛めっき処理、クロメート処理等を施している。
なお、電解銅箔の場合は、通常Ｍ面に粗化処理を施し、Ｓ面には、通常粗化処理はせず、防錆或いは耐熱変色を抑える目的で亜鉛めっき処理、クロメート処理等を施している。
Both the rolled copper foil and the electrolytic copper foil used for FPC are subjected to a roughening treatment in which copper particles are adhered to at least the surface of the copper foil that adheres to the film in order to increase the adhesive strength with the insulating film. The surface is subjected to galvanization and chromate treatment to prevent rust and heat discoloration.
In the case of electrolytic copper foil, the M surface is usually roughened, and the S surface is not normally roughened, but is galvanized or chromated to prevent rust or heat discoloration. ing.
ＣＣＬ製造時には、この粗化処理面に接着樹脂を介してフィルムを熱圧着させ（三層ＦＰＣ）、或いは接着樹脂を介さず粗化処理面に直接キャスティング或いは熱圧着法により、絶縁フィルムを積層（二層ＦＰＣ）してＣＣＬを作成する。
作成したＣＣＬにエッチング法により回路を形成し、回路側に絶縁フィルムのカバーレイを接着してＦＰＣとする。
At the time of CCL production, an insulating film is laminated on the roughened surface by thermo-compression (three-layer FPC) or directly on the roughened surface without using an adhesive resin. Create a CCL by double-layer FPC).
A circuit is formed on the prepared CCL by an etching method, and an insulating film cover lay is adhered to the circuit side to form an FPC.
このようにして作成したＦＰＣは折り曲げられて装着され、或いは繰り返して曲げられる箇所に使用される。従って、ＦＰＣ用銅箔は、屈曲性に優れていることが必要である。 The FPC produced in this way is used by being bent and mounted or repeatedly bent. Therefore, the copper foil for FPC needs to be excellent in flexibility.
なお、屈曲性の評価試験方法としては、ＪＩＳ Ｃ ５０１６−１９９４に記載されている耐折性試験、あるいはＩＰＣ規格ＴＭ−６５０に記載されている耐屈曲性試験等がある。この内、ＩＰＣ規格ＴＭ−６５０に記載の耐屈曲性試験は、ＦＰＣが使用される実際の曲げモードに近い試験方法と言われており、一般的に使用されている。本明細書における表面粗化処理銅箔の屈曲性試験はこのＩＰＣ規格ＴＭ−６５０に記載された試験法方にて測定している。 In addition, as an evaluation test method for bendability, there are a bend resistance test described in JIS C 5016-1994, a bend resistance test described in IPC standard TM-650, and the like. Among them, the bending resistance test described in the IPC standard TM-650 is said to be a test method close to an actual bending mode in which FPC is used, and is generally used. The bendability test of the surface roughened copper foil in this specification is measured by the test method described in this IPC standard TM-650.
上記のような耐屈曲性試験によりＦＰＣの屈曲試験を行うと、屈曲回数が多くなるに従い銅箔表面から亀裂が入り、その亀裂を起点にして最終的には銅箔が破断する。
亀裂が入る過程を詳細に観察すると、図２に模式図で示すように粗化処理の粒界から先ず亀裂が入り、屈曲を繰り返すことで亀裂は銅箔内部に進行し、図３に示すように箔の破断に至る。
When the bending test of the FPC is performed by the bending resistance test as described above, a crack enters the copper foil surface as the number of bending increases, and the copper foil eventually breaks starting from the crack.
When the process of cracks is observed in detail, cracks first enter from the grain boundaries of the roughening treatment as shown in the schematic diagram of FIG. 2, and the cracks progress inside the copper foil by repeating the bending, as shown in FIG. This leads to the breaking of the foil.
この現象について解析を行ったところ、粗化処理で施した粗化粒子は銅箔表面に細かい結晶として箔表面に密集していて靭性が低く、このため粗化処理層の凹凸の谷部が起点となってクラックが発生し(図２参照)、屈曲が繰り返されるに従って起点となるクラックから破断が始まる、との見解を得た。 When this phenomenon was analyzed, the roughened particles applied in the roughening treatment were dense on the surface of the foil as fine crystals, and the toughness was low. As a result, a crack was generated (see FIG. 2), and it was obtained that the fracture started from the crack as the starting point as the bending was repeated.
本発明は、上記見解に基づき、従来の電解銅箔の屈曲寿命をさらに高めることを目的に鋭意研究し、本発明を完成させた。
本発明は絶縁フィルムと接着する接着性に優れ、かつ、絶縁フィルムと接着後の耐屈曲性に優れるフレキシブルプリント配線板用銅箔を提供することを目的とする。
また、本発明は絶縁フィルムと接着する接着性に優れ、かつ、絶縁フィルムと接着後の耐屈曲性に優れる回路基板、特にフレキシブルプリント配線板用銅箔とその製造方法を提供することを目的とする。
Based on the above view, the present invention has been intensively studied for the purpose of further increasing the bending life of the conventional electrolytic copper foil, and the present invention has been completed.
An object of this invention is to provide the copper foil for flexible printed wiring boards which is excellent in the adhesiveness which adhere | attaches with an insulating film, and is excellent in the bending resistance after adhesion | attachment with an insulating film.
Another object of the present invention is to provide a circuit board, particularly a copper foil for a flexible printed wiring board, and a method for producing the same, which are excellent in adhesiveness to be bonded to an insulating film and excellent in bending resistance after bonding to the insulating film. To do.
本発明の表面粗化処理銅箔は、未処理銅箔の少なくとも片面に表面粗化処理層を施した銅箔であって、該銅箔を３００℃で１時間加熱し、ＪＩＳ Ｃ ５０１６−１９９４の付図４に記載のライン／スペース＝１．５ｍｍ×１．０ｍｍの回路に加工した後、屈曲速度１５００回／分、ストローク長さ２０．０ｍｍ、曲率半径１．０ｍｍの条件で、ＩＰＣ屈曲試験（ＩＰＣ規格ＴＭ−６５０に準拠）を行った結果、耐屈曲回数が１１，０００回以上であり、かつ、該表面粗化処理層を施した銅箔を３００°Ｃで１時間加熱した後の粗化粒子を構成する銅の平均結晶粒径が０．５μｍ以上で、表面積比が１．１〜５．０である表面粗化処理銅箔である。
ここで、表面積比とは、銅箔の表面に上記粗化処理を行い、その後、上記加熱処理したことより銅箔の結晶組織が粗大化して銅箔の表面積がどの程度変化したかを示す銅箔の表面積の変化の比率を言う。
The surface-roughened copper foil of the present invention is a copper foil in which a surface-roughened layer is applied to at least one surface of an untreated copper foil, the copper foil is heated at 300 ° C. for 1 hour, and JIS C 5016-1994. After processing into a circuit of line / space = 1.5 mm × 1.0 mm shown in FIG. 4, the IPC bending test was performed under the conditions of a bending speed of 1500 times / minute, a stroke length of 20.0 mm, and a curvature radius of 1.0 mm. As a result of performing (based on IPC standard TM-650), the number of bending resistances was 11,000 times or more, and the copper foil coated with the surface roughening treatment layer was heated at 300 ° C. for 1 hour. The surface-roughened copper foil has an average crystal grain size of copper constituting the roughened particles of 0.5 μm or more and a surface area ratio of 1.1 to 5.0.
Here, the surface area ratio is the copper that indicates how much the surface area of the copper foil has changed due to the coarsening of the crystal structure of the copper foil by performing the above roughening treatment on the surface of the copper foil and then the above heat treatment. The ratio of the change in the surface area of the foil.
好ましくは、３００℃で１時間加熱した後の当該表面粗化処理銅箔の０．２％耐力が１６０Ｎ／ｍｍ2以下である。
Preferably, the 0.2% proof stress of the surface roughened copper foil after heating at 300 ° C. for 1 hour is 160 N / mm 2 or less.
前記表面粗化処理層の上に、Ｎｉ、Ｚｎ、Ｃｒ、Ｃｏ、Ｍｏ、Ｐの単体、またはそれらの合金、またはそれらの水和物の少なくとも１種類以上が含まれる表面保護層が形成されていることが好ましい。 On the surface roughening layer, a surface protective layer containing at least one of Ni, Zn, Cr, Co, Mo, P alone, an alloy thereof, or a hydrate thereof is formed. Preferably it is.
本発明の表面粗化処理銅箔の製造方法は、上記表面粗化処理銅箔の製造方法であって、前記未処理銅箔の少なくとも片面を、チオ尿素、エチレンチオ尿素、または、チオセミカルバジド尿素が０．００１ｍｍｏｌ／Ｌ〜０．１ｍｍｏｌ／Ｌ添加された電解液で表面粗化処理し、少なくとも片面に表面粗化処理層を有する銅箔を製造する表面粗化処理銅箔の製造方法である。
Method for producing a surface-roughened copper foil of the present invention is a manufacturing method of the surface roughening treatment of copper foil, at least one surface of the untreated copper foil, thiourea, ethylene thiourea, or the thiosemicarbazide urea It is a manufacturing method of the surface roughening process copper foil which manufactures the copper foil which carries out the surface roughening process with the electrolyte solution added 0.001 mmol / L-0.1 mmol / L, and has a surface roughening process layer at least on one side.
本発明の回路基板は、本発明の表面粗化処理銅箔にフィルムを貼り付けてなる回路基板である。 The circuit board of the present invention is a circuit board obtained by attaching a film to the surface roughened copper foil of the present invention.
本発明の表面処理銅箔は、絶縁フィルムと接着する接着性に優れ、かつ、絶縁フィルムと高温での接着後の耐屈曲性に優れる回路基板用、特にフレキシブルプリント配線板用の表
面粗化処理銅箔を提供することができる。
また、本発明は絶縁フィルムと接着する接着性に優れ、かつ、絶縁フィルムと高温での接着後の耐屈曲性に優れるフレキシブルプリント配線板用銅箔の製造方法を提供することができる。
更に、本発明は耐屈曲性に優れたフレキシブルプリント配線板（ＦＰＣ）等の回路基板を提供することができる。
The surface-treated copper foil of the present invention is excellent in adhesiveness for adhering to an insulating film, and has a surface roughening treatment for a circuit board, particularly for a flexible printed wiring board, which has excellent bending resistance after adhesion to an insulating film at a high temperature. Copper foil can be provided.
Moreover, this invention can provide the manufacturing method of the copper foil for flexible printed wiring boards which is excellent in the adhesiveness which adhere | attaches with an insulating film, and is excellent in the bending resistance after adhesion | attachment with an insulating film at high temperature.
Furthermore, this invention can provide circuit boards, such as a flexible printed wiring board (FPC) excellent in bending resistance.
本発明は、表面処理を施していない電解銅箔、圧延銅箔（以下、未処理銅箔又は単に銅箔と表現することがある）の少なくとも片面に、粒状又は柱状の結晶組織からなる表面処理層が設けられている回路基板（例えばフレキシブルプリント配線板）用銅箔である。
本発明において未処理電解銅箔は、電解銅箔、圧延銅箔いずれでもよく、製箔後の再結晶処理で結晶粒が粗大化する銅箔であれば何れでもよい。
The present invention provides a surface treatment comprising a granular or columnar crystal structure on at least one surface of an electrolytic copper foil and a rolled copper foil (hereinafter sometimes referred to as an untreated copper foil or simply a copper foil) that have not been subjected to a surface treatment. A copper foil for a circuit board (for example, a flexible printed wiring board) provided with a layer.
In the present invention, the untreated electrolytic copper foil may be either an electrolytic copper foil or a rolled copper foil, and any copper foil can be used as long as the crystal grains are coarsened by the recrystallization treatment after the foil formation.
図１は表面処理銅箔の結晶組織を説明するための模式図であり、図１（イ）は未処理銅箔１に表面処理を施して粗化粒子２を付着させた状態を示している。この粗化処理した表面処理銅箔を再結晶処理すると、通常の粗化処理方法で粗化処理した表面粗化銅箔は図１（ロ）に示すように銅箔１は再結晶するが粗化粒子２は再結晶しない。
本発明の表面処理銅箔は、図１（ハ）に示すように、粗化処理後に再結晶処理を施すと粗化粒子も銅箔と共に再結晶し、結晶組織が粗大化して銅箔本体と表面粗化粒子とが一体化される。
このように、銅箔本体と表面粗化処理粒子とが一体化して結晶組織が粗大化する。従ってこの銅箔に繰り返し屈曲作用を施し、粗面表面凹凸の凹の部分に応力を集中させても、結晶組織が粗大化して靭性が向上し、亀裂が発生し難く、耐屈曲性に優れ、絶縁基板との接着性に優れる表面処理銅箔となると推考される。
FIG. 1 is a schematic diagram for explaining the crystal structure of a surface-treated copper foil, and FIG. 1 (a) shows a state in which roughened
As shown in FIG. 1 (c), the surface-treated copper foil of the present invention is recrystallized after the roughening treatment, so that the roughened particles are recrystallized together with the copper foil, and the crystal structure is coarsened. Surface roughening particles are integrated.
Thus, the copper foil body and the surface roughening particles are integrated to coarsen the crystal structure. Therefore, even if the copper foil is repeatedly bent and stress is concentrated on the concave portion of the rough surface, the crystal structure is coarsened and the toughness is improved, cracks are hardly generated, and the bending resistance is excellent. It is assumed that the surface-treated copper foil is excellent in adhesiveness with the insulating substrate.
通常の粗化処理方法で表面処理した銅箔は表面処理した粒子が再結晶しない、或いはし難いため、銅箔本体の結晶組織が再結晶して粗大化しても表面の粗化粒子は粗大化しない（図１ロ参照）。従って、このような表面処理銅箔に再結晶処理を施しても耐屈曲性を向上させることは望めない。再結晶処理で表面粗化粒子が銅箔本体と共に再結晶し、結晶組織が粗大化することで、初めて耐屈曲性の良い電解銅箔を得ることができる。
なおここで言う通常の粗化処理方法とは、硫酸銅を主成分とし、無機添加剤を添加した浴でヤケめっき処理により行う手法である。無機添加剤として代表的なものはＦｅ、Ｗ、Ｍｏ、Ｃｏ、Ｎｉ、Ｃｒの金属イオンが挙げられる。
Copper foil that has been surface-treated by the usual roughening treatment method does not recrystallize or is difficult to recrystallize, so even if the crystal structure of the copper foil body is recrystallized and coarsened, the roughened particles on the surface become coarse No (see Figure 1 b). Therefore, even if recrystallization treatment is applied to such a surface-treated copper foil, it cannot be expected to improve the bending resistance. The surface-roughened particles are recrystallized together with the copper foil body by the recrystallization treatment, and the crystal structure is coarsened, whereby an electrolytic copper foil having good bending resistance can be obtained for the first time.
In addition, the normal roughening processing method said here is the method performed by burnt plating processing in the bath which has copper sulfate as a main component and added the inorganic additive. Typical examples of inorganic additives include metal ions of Fe, W, Mo, Co, Ni, and Cr.
再結晶処理で結晶組織が粗大化する粒子を施すには、チオ尿素系添加剤を添加した硫酸銅電解液で表面処理することで可能となる。このようにして表面処理を施した銅箔を再結晶処理することで、粗化粒子を構成する銅の結晶組織が粗大化し、銅箔本体と共に粗大化した結晶組織となる。
なお、上記粗化方法は一例であり、本発明においては、前記粗化方法により表面粗化された銅箔に限定されるものではない。
In order to apply particles whose crystal structure is coarsened by recrystallization treatment, it is possible to perform surface treatment with a copper sulfate electrolytic solution to which a thiourea additive is added. By recrystallizing the surface-treated copper foil in this way, the crystal structure of copper constituting the coarse particles is coarsened, and becomes a coarse crystal structure together with the copper foil body.
In addition, the said roughening method is an example and in this invention, it is not limited to the copper foil surface-roughened by the said roughening method.
銅箔に表面処理を施すめっき処理によっては形成される銅の結晶組織は、そのめっき液組成により柱状の結晶組織となる場合がある。しかし、未処理電解銅箔に施すめっきとしては、柱状組織のめっきは耐屈曲性が必要とされる場合には適さない。その理由は、銅箔に曲げ応力が加わったとき、柱状の結晶組織の場合、柱状の結晶粒界にそって亀裂がはいり、破断する確率が高いためである。
しかし、結晶組織が柱状粗化粒子も、該粗化粒子を再結晶させることで粒状の結晶組織とすることができる場合がある。このような場合には先ず柱状結晶組織の粗化処理を施し、次いで再結晶させて粒状結晶組織とすることができるので、柱状の結晶組織となる表面処理も有効である。
Depending on the plating treatment in which the copper foil is subjected to a surface treatment, the copper crystal structure formed may become a columnar crystal structure depending on the composition of the plating solution. However, as plating applied to the untreated electrolytic copper foil, columnar structure plating is not suitable when bending resistance is required. The reason is that, when a bending stress is applied to the copper foil, in the case of a columnar crystal structure, a crack is generated along the columnar crystal grain boundary and the probability of fracture is high.
However, columnar roughened particles having a crystal structure may sometimes be formed into a granular crystal structure by recrystallizing the roughened particles. In such a case, the columnar crystal structure can be first roughened and then recrystallized to form a granular crystal structure. Therefore, a surface treatment for forming a columnar crystal structure is also effective.
本発明の銅箔は、好適には、表面処理銅箔の少なくとも一方の面の表面粗さＲz（表面粗度）が０．５〜５．０μｍであり、かつ、表面積比が１．１〜５．０の粗化処理層が設けられている。
ここで、表面積比とは、銅箔の表面に上記粗化処理を行い、その後、上記加熱処理したことより銅箔の結晶組織が粗大化して銅箔の表面積がどの程度変化したかを示す銅箔の表面積の変化の比率を言う。
なお、粗化処理および加熱処理を行う前の銅箔の表面、および、粗化処理および加熱処理を行った後の銅箔の表面には凹凸があるから、上記表面積比の算出に際しては、それらの銅箔の表面積を測定した領域を凹凸のない完全な平面として扱う。
前記表面処理銅箔の表面粗度Ｒzを０．５〜５．０μｍとするのは、Ｒｚが０．５μｍ以下では銅箔表面に張付ける絶縁フィルムとの間で十分な投錨効果が得られず、密着性に乏しいためであり、Ｒｚが５．０μｍ以上では、配線を形成する際のエッチング時に、根残りが発生しやすくなり、エッチングファクターが低下するため好ましくないためである。
また、前記表面処理銅箔の表面積比を１．１〜５．０倍とするのは、表面積比が１．１倍以下では絶縁フィルムとの間で十分な投錨効果が得られず、密着性に乏しいためであり、５．０倍以上では粗面の粗さが粗く、そこから亀裂がはいる恐れがあるため、好ましくないからである。
The copper foil of the present invention preferably has a surface roughness Rz (surface roughness) of at least one surface of the surface-treated copper foil of 0.5 to 5.0 μm and a surface area ratio of 1.1 to 1.1. A roughening treatment layer of 5.0 is provided.
Here, the surface area ratio is the copper that indicates how much the surface area of the copper foil has changed due to the coarsening of the crystal structure of the copper foil by performing the above roughening treatment on the surface of the copper foil and then the above heat treatment. The ratio of the change in the surface area of the foil.
In addition, since the surface of the copper foil before performing the roughening treatment and the heat treatment and the surface of the copper foil after performing the roughening treatment and the heat treatment are uneven, in calculating the surface area ratio, The area where the surface area of the copper foil was measured is treated as a complete flat surface without irregularities.
The surface roughness Rz of the surface-treated copper foil is set to 0.5 to 5.0 μm because, when Rz is 0.5 μm or less, a sufficient anchoring effect cannot be obtained with the insulating film attached to the copper foil surface. This is because the adhesiveness is poor, and when Rz is 5.0 μm or more, root residue tends to occur during etching when forming the wiring, and the etching factor decreases, which is not preferable.
In addition, the surface-treated copper foil has a surface area ratio of 1.1 to 5.0 times because, when the surface area ratio is 1.1 times or less, a sufficient anchoring effect cannot be obtained with the insulating film, and adhesion This is because if the surface is 5.0 times or more, the roughness of the rough surface is large and cracks may be generated from the rough surface.
本発明における再結晶処理は、一般的な再結晶処理方法、例えば任意時間加熱処理する方法で施すことができる。また、再結晶処理としてＦＰＣを製造する際の熱履歴を利用することもでき、例えば、ポリイミドフィルムと積層するための熱履歴として代表的な３００℃、1時間を選択して再結晶することも可能である。 The recrystallization treatment in the present invention can be performed by a general recrystallization treatment method, for example, a heat treatment method for an arbitrary time. Moreover, the heat history at the time of manufacturing FPC can also be used as the recrystallization process. For example, as a heat history for laminating with a polyimide film, a typical 300 ° C., 1 hour can be selected and recrystallized. Is possible.
本発明の銅箔は、３００℃×１時間加熱した後の０．２％耐力が１６０Ｎ／ｍｍ２以下であることが好ましい。０．２
％耐力が１６０／ｍｍ２以上では靭性に乏しく、屈曲性が低下する不具合が生じるためである。なお、下限は１００Ｎ／ｍｍ２程度である。
The copper foil of the present invention preferably has a 0.2% proof stress of 160 N / mm 2 or less after heating at 300 ° C. for 1 hour. 0.2
This is because when the% proof stress is 160 / mm 2 or more, the toughness is poor and the flexibility is lowered. The lower limit is about 100 N / mm 2 .
本発明の表面処理方法はチオ尿素系化合物を添加した硫酸銅電解液で電解処理する。
チオ尿素系化合物の添加量は０.１ｍｍｏｌ／Ｌ以下、好ましくは０.００１〜０.１ｍｍｏｌ／Ｌである。添加量が０.１ｍｍｏｌ／Ｌより多く添加すると粗化粒子の結晶組織が粗大化せず、軟化特性を示さなくなるので好ましくない。添加量が０．００１ｍｍｏｌ／Ｌ未満では、添加剤としての効果が発揮されず、粗化粒子が均一に電着しない。
In the surface treatment method of the present invention, electrolytic treatment is performed with a copper sulfate electrolyte containing a thiourea compound.
The addition amount of the thiourea compound is 0.1 mmol / L or less, preferably 0.001 to 0.1 mmol / L. When the addition amount is more than 0.1 mmol / L, the crystal structure of the roughened particles is not coarsened and softening characteristics are not exhibited, which is not preferable. When the addition amount is less than 0.001 mmol / L, the effect as an additive is not exhibited, and the roughened particles are not electrodeposited uniformly.
このようにして形成した表面粗化処理層は、２５０〜３５０℃で再結晶する。従って、２５０〜３５０℃で再結晶処理することで、銅箔本体と表面粗化処理層の結晶組織を一体化させることができる。また、ポリイミド基板と積層する場合のように積層温度が高い銅張積層板（二層構造、三層構造共に）製造時の加熱（例えば３００℃×１時間）により再結晶することも可能である。
このように、再結晶して結晶組織が粗大化した銅箔は、ＦＰＣに曲げ応力がかかった場合でも銅箔に亀裂が入りにくく、銅箔の屈曲破断に至る屈曲回数が増える。従来手法で作成された粗化処理銅箔に対し、本発明の手法で作成された粗化処理銅箔は、後述するように加熱(３００℃、１時間)後の屈曲回数が少なくとも１０％増加する。
The surface roughened layer thus formed is recrystallized at 250 to 350 ° C. Therefore, by recrystallizing at 250 to 350 ° C., the crystal structure of the copper foil body and the surface roughened layer can be integrated. Moreover, it is also possible to recrystallize by heating (for example, 300 ° C. × 1 hour) at the time of manufacturing a copper clad laminate (both two-layer structure and three-layer structure) having a high lamination temperature as in the case of lamination with a polyimide substrate. .
As described above, the copper foil whose crystal structure has been coarsened by recrystallization hardly cracks the copper foil even when bending stress is applied to the FPC, and the number of times of bending leading to bending fracture of the copper foil increases. Compared to the roughened copper foil prepared by the conventional method, the roughened copper foil prepared by the method of the present invention increases the number of bendings after heating (300 ° C., 1 hour) by at least 10% as described later. To do.
本発明において、表面粗化処理層を施した銅箔の３００℃×１時間加熱後のＩＰＣ屈曲試験（ＩＰＣ規格ＴＭ−６５０）による耐屈曲回数は１１，０００回以上である。耐屈曲回数が１１，０００回以上と耐屈曲性に優れるのは銅箔表面が再結晶して結晶組織が粗大化し、銅箔に曲げ応力がかかった場合でも亀裂が入りにくく、銅箔の屈曲破断に至る屈曲回数が増えるためである。加熱処理しても再結晶しない結晶組織では、図２、図３に示すように粗化粒子を構成する銅の粒界から亀裂が入るため、例えば無機添加剤を添加した粗化処理液で粗化処理した表面処理銅箔では１１，０００回以上の耐屈曲性を付与することはできない。
In the present invention, the number of times of bending resistance by the IPC bending test (IPC standard TM-650) after heating the surface-roughened layer of the copper foil at 300 ° C. for 1 hour is 11,000 times or more. The bending resistance is 11,000 times or more, which is excellent in bending resistance. The surface of the copper foil is recrystallized, the crystal structure becomes coarse, and even when bending stress is applied to the copper foil, it is difficult to crack and the copper foil is bent. This is because the number of times of bending leading to breakage increases. In the crystal structure that does not recrystallize even when heat-treated, cracks enter from the grain boundaries of the copper constituting the roughened particles as shown in FIGS. The surface-treated copper foil that has been subjected to the chemical treatment cannot provide bending resistance of 11,000 times or more.
本発明は、材料力学の観点から、銅箔を繰返して曲げるとき銅箔最外層に最も大きな応力が加わり、最外層の粒界から最初に亀裂が発生することに着目し、このメカニズムによる亀裂発生を抑制するため、最外層に加熱により再結晶する粒界を形成した。加熱後に結晶粒が粗大化（粗化粒子を構成する銅の平均結晶粒径が０．５μｍ以上）することで靭性が向上し、耐屈曲に優れる表面処理銅箔となる。
このように最外層に加熱により再結晶する粒界を形成することで、粗化粒子を構成する銅の平均結晶粒径が０．５μｍ以上となり、耐屈曲回数が１１，０００回以上となる表面処理銅箔となる。
このように本実施形態の銅箔を用いたＦＰＣ製品は、今後益々厳しい屈曲性が求められるＦＰＣ製品に対して長期信頼性・長寿命を確保できる。
From the viewpoint of material mechanics, the present invention pays attention to the fact that when the copper foil is repeatedly bent, the largest stress is applied to the outermost layer of the copper foil, and cracks are first generated from the grain boundary of the outermost layer. In order to suppress this, a grain boundary recrystallized by heating was formed in the outermost layer. When the crystal grains are coarsened after heating ( the average crystal grain diameter of copper constituting the coarsened particles is 0.5 μm or more), the toughness is improved and a surface-treated copper foil having excellent bending resistance is obtained.
By forming a grain boundary that is recrystallized by heating in the outermost layer in this way, the average crystal grain size of copper constituting the roughened particles is 0.5 μm or more, and the number of bending resistances is 11,000 times or more. It becomes a treated copper foil.
As described above, the FPC product using the copper foil of the present embodiment can ensure long-term reliability and a long service life as compared with an FPC product that is required to have increasingly strict flexibility in the future.
本発明の表面粗化処理銅箔の表面に表面保護層を設けることで、粗化処理層表面を防錆し、耐熱性を高めることができる。
表面保護層としては表面粗化処理層上に設けることは勿論、粗化処理を施さない方の面にも同様に施すことが好ましい。
表面保護層としては、Ｎｉ、Ｚｎ、Ｃｒ、Ｃｏ、Ｍｏ、Ｐの単体、またはそれらの合金、またはそれらの水和物の少なくとも１種類以上が含まれる層を施すことが好ましい。
By providing a surface protective layer on the surface of the surface roughened copper foil of the present invention, the surface of the roughened layer can be rusted and heat resistance can be increased.
The surface protective layer is preferably provided on the surface roughening treatment layer as well as the surface not subjected to the roughening treatment.
As the surface protective layer, it is preferable to apply a layer containing at least one of Ni, Zn, Cr, Co, Mo, P alone, an alloy thereof, or a hydrate thereof.
以下本発明を実施例によりさらに詳しく説明する。
粗化処理を行う銅箔（未処理銅箔）には、特開２００８-１３８４７の製法に順ずる電解銅箔(厚さ＝７μｍ、以下電解銅箔Ａと記載)、特開平８−２８３８８６の製法に順ずる電解銅箔(厚さ＝７μｍ、以下電解銅箔Ｂと記載)、及び市販品の圧延銅箔(厚さ＝７μｍ、タフピッチ銅、アズロール箔)を用いた。
Hereinafter, the present invention will be described in more detail with reference to examples.
For the copper foil to be roughened (untreated copper foil), an electrolytic copper foil (thickness = 7 μm, hereinafter referred to as electrolytic copper foil A) conforming to the production method of Japanese Patent Application Laid-Open No. 2008-138847, Electrolytic copper foil (thickness = 7 μm, hereinafter referred to as electrolytic copper foil B) conforming to the production method and commercially available rolled copper foil (thickness = 7 μm, tough pitch copper, azurol foil) were used.
〈実施例１〜５〉
未処理銅箔は電解銅箔Ａを使用し、下記条件で表面粗化処理した。
表面粗化処理は、表面処理浴組成１のめっき液を使用してＭ面に２μｍの厚さにめっきを行った。
電解浴組成１：
Ｃｕ＝７８７〜２３６０ｍｍｏｌ／Ｌ
Ｈ2ＳＯ4＝２０５〜２０５０ｍｍｏｌ／Ｌ
Ｃｌ＝４２４〜１４１０ｍｍｏｌ／Ｌ
チオ尿素＝０．００１〜０．１ｍｍｏｌ／Ｌ
電解条件：
電流密度＝２０〜６０Ａ／ｄｍ２
浴温：４０〜６０℃
次いで表面処理した銅箔を３００℃で１時間加熱して再結晶処理を行った。
<Examples 1-5>
As the untreated copper foil, electrolytic copper foil A was used, and the surface was roughened under the following conditions.
In the surface roughening treatment, the M surface was plated to a thickness of 2 μm using a plating solution of surface
Electrolytic bath composition 1:
Cu = 787-2360 mmol / L
H 2 SO 4 = 205~2050mmol / L
Cl = 424-1410 mmol / L
Thiourea = 0.001 to 0.1 mmol / L
Electrolysis conditions:
Current density = 20-60 A / dm 2
Bath temperature: 40-60 ° C
Next, the surface-treated copper foil was recrystallized by heating at 300 ° C. for 1 hour.
〈実施例６〉
未処理銅箔は電解銅箔Ａを使用し、下記条件で表面処理した。
表面処理は、表面処理浴組成２のめっき液を使用してＭ面に２μｍの厚さにめっきを行った。
電解浴組成２：
Ｃｕ＝７８７〜２３６０ｍｍｏｌ／Ｌ
Ｈ2ＳＯ4＝２０５〜２０５０ｍｍｏｌ／Ｌ
Ｃｌ＝４２４〜１４１０ｍｍｏｌ／Ｌ
エチレンチオ尿素＝０．０１ｍｍｏｌ／Ｌ
電解条件：
電流密度＝２０〜６０Ａ／ｄｍ２
浴温：４０〜６０℃
次いで表面処理した銅箔を３００℃で１時間加熱して再結晶処理を行った。
<Example 6>
The untreated copper foil used electrolytic copper foil A, and was surface-treated under the following conditions.
In the surface treatment, plating was performed on the M surface to a thickness of 2 μm using a plating solution of surface
Electrolytic bath composition 2:
Cu = 787-2360 mmol / L
H 2 SO 4 = 205~2050mmol / L
Cl = 424-1410 mmol / L
Ethylenethiourea = 0.01mmol / L
Electrolysis conditions:
Current density = 20-60 A / dm 2
Bath temperature: 40-60 ° C
Next, the surface-treated copper foil was recrystallized by heating at 300 ° C. for 1 hour.
〈実施例７〉
未処理銅箔は電解銅箔Ａを使用し、下記条件で表面処理した。
表面処理は、表面処理浴組成３のめっき液を使用してＭ面に２μｍの厚さにめっきを行った。
電解浴組成３：
Ｃｕ＝７８７〜２３６０ｍｍｏｌ（ミリモル）／Ｌ（リットル）
Ｈ２ＳＯ４＝２０５〜２０５０ｍｍｏｌ／Ｌ
Ｃｌ＝４２４〜１４１０ｍｍｏｌ／Ｌ
チオセミカルバジド＝０．０１ｍｍｏｌ／Ｌ
電解条件：
電流密度＝２０〜６０Ａ／ｄｍ２
浴温：４０〜６０℃
次いで表面処理した銅箔を３００℃で１時間加熱して再結晶処理を行った。
<Example 7>
The untreated copper foil used electrolytic copper foil A, and was surface-treated under the following conditions.
In the surface treatment, plating was performed on the M surface to a thickness of 2 μm using a plating solution of surface treatment bath composition 3.
Electrolytic bath composition 3:
Cu = 787-2360mmol (mmol) / L (liter)
H 2 SO 4 = 205~2050mmol / L
Cl = 424-1410 mmol / L
Thiosemicarbazide = 0.01mmol / L
Electrolysis conditions:
Current density = 20-60 A / dm 2
Bath temperature: 40-60 ° C
Next, the surface-treated copper foil was recrystallized by heating at 300 ° C. for 1 hour.
〈実施例８〉
未処理銅箔は電解銅箔Ｂを使用し、下記条件で表面処理した。
表面処理は、表面処理浴組成４のめっき液を使用してＭ面に２μｍの厚さにめっきを行った。
電解浴組成４：
Ｃｕ＝７８７〜２３６０ｍｍｏｌ／Ｌ
Ｈ2ＳＯ4＝２０５〜２０５０ｍｍｏｌ／Ｌ
Ｃｌ＝４２４〜１４１０ｍｍｏｌ／Ｌ
チオ尿素＝０．０１ｍｍｏｌ／Ｌ
電解条件：
電流密度＝２０〜６０Ａ／ｄｍ２
浴温： ４０〜６０℃
次いで表面処理した銅箔を３００℃で１時間加熱して再結晶処理を行った。
<Example 8>
The untreated copper foil used electrolytic copper foil B and was surface-treated under the following conditions.
In the surface treatment, plating was performed on the M surface to a thickness of 2 μm using a plating solution of surface
Electrolytic bath composition 4:
Cu = 787-2360 mmol / L
H 2 SO 4 = 205~2050mmol / L
Cl = 424-1410 mmol / L
Thiourea = 0.01mmol / L
Electrolysis conditions:
Current density = 20-60 A / dm 2
Bath temperature: 40-60 ° C
Next, the surface-treated copper foil was recrystallized by heating at 300 ° C. for 1 hour.
〈実施例９〉
未処理銅箔に圧延銅箔を使用し、下記条件で表面処理した。
表面処理は、表面処理浴組成５のめっき液を使用してＭ面に２μｍの厚さにめっきを行った。
電解浴組成５：
Ｃｕ＝７８７〜２３６０ｍｍｏｌ／Ｌ
Ｈ2ＳＯ4＝２０５〜２０５０ｍｍｏｌ／Ｌ
Ｃｌ＝４２４〜１４１０ｍｍｏｌ／Ｌ
チオ尿素＝０．０１ｍｍｏｌ／Ｌ
電解条件：
電流密度＝２０〜６０Ａ／ｄｍ２
浴温：４０〜６０℃
次いで表面処理した銅箔を３００℃で１時間加熱して再結晶処理を行った。
<Example 9>
Rolled copper foil was used for untreated copper foil, and surface treatment was performed under the following conditions.
In the surface treatment, plating was performed on the M surface to a thickness of 2 μm using a plating solution of surface treatment bath composition 5.
Electrolytic bath composition 5:
Cu = 787-2360 mmol / L
H 2 SO 4 = 205~2050mmol / L
Cl = 424-1410 mmol / L
Thiourea = 0.01mmol / L
Electrolysis conditions:
Current density = 20-60 A / dm 2
Bath temperature: 40-60 ° C
Next, the surface-treated copper foil was recrystallized by heating at 300 ° C. for 1 hour.
＜比較例１＞
実施例１と同じ電解銅箔Ａを使用し、下記条件で表面処理した。
表面処理は、表面処理浴組成６のめっき液を使用してＭ面に２μｍの厚さにめっきを行った。
電解浴組成６：
Ｃｕ＝７８７〜２３６０ｍｍｏｌ／Ｌ
Ｈ2ＳＯ4＝２０５〜２０５０ｍｍｏｌ／Ｌ
Ｃｌ＝４２４〜１４１０ｍｍｏｌ／Ｌ
電解条件：
電流密度＝２０〜６０Ａ／ｄｍ２
浴温：４０〜６０℃
次いで表面処理した銅箔を３００℃で１時間加熱して再結晶処理を行った。
<Comparative Example 1>
The same electrolytic copper foil A as in Example 1 was used, and surface treatment was performed under the following conditions.
In the surface treatment, plating was performed on the M surface to a thickness of 2 μm using a plating solution of surface treatment bath composition 6.
Electrolytic bath composition 6:
Cu = 787-2360 mmol / L
H 2 SO 4 = 205~2050mmol / L
Cl = 424-1410 mmol / L
Electrolysis conditions:
Current density = 20-60 A / dm 2
Bath temperature: 40-60 ° C
Next, the surface-treated copper foil was recrystallized by heating at 300 ° C. for 1 hour.
＜比較例２〜４＞
未処理銅箔は電解銅箔Ａを使用し、下記条件で表面処理した。
表面処理は、表面処理浴組成７のめっき液を使用してＭ面に２μｍの厚さにめっきを行った。
電解浴組成７：
Ｃｕ＝７８７〜２３６０ｍｍｏｌ／Ｌ
Ｈ2ＳＯ4＝２０５〜２０５０ｍｍｏｌ／Ｌ
Ｃｌ＝４２４〜１４１０ｍｍｏｌ／Ｌ
無機添加剤（硫酸鉄七水和物）＝０．００１〜０．１ｍｍｏｌ／Ｌ
電解条件：
電流密度＝２０〜６０Ａ／ｄｍ２
浴温：４０〜６０℃
次いで表面処理した銅箔を３００℃で１時間加熱して再結晶処理を行った。
<Comparative Examples 2-4>
The untreated copper foil used electrolytic copper foil A, and was surface-treated under the following conditions.
In the surface treatment, plating was performed on the M surface to a thickness of 2 μm using a plating solution of surface treatment bath composition 7.
Electrolytic bath composition 7:
Cu = 787-2360 mmol / L
H 2 SO 4 = 205~2050mmol / L
Cl = 424-1410 mmol / L
Inorganic additive (iron sulfate heptahydrate) = 0.001 to 0.1 mmol / L
Electrolysis conditions:
Current density = 20-60 A / dm 2
Bath temperature: 40-60 ° C
Next, the surface-treated copper foil was recrystallized by heating at 300 ° C. for 1 hour.
＜比較例５＞
未処理銅箔は電解銅箔Ｂを使用し、下記条件で表面処理した。
表面処理は、表面処理浴組成８のめっき液を使用してＭ面に２μｍの厚さにめっきを行った。
電解浴組成８：
Ｃｕ＝７８７〜２３６０ｍｍｏｌ／Ｌ
Ｈ2ＳＯ4＝２０５〜２０５０ｍｍｏｌ／Ｌ
Ｃｌ＝４２４〜１４１０ｍｍｏｌ／Ｌ
無機添加剤（硫酸鉄七水和物）＝０．０１ｍｍｏｌ／Ｌ
電解条件：
電流密度＝２０〜６０Ａ／ｄｍ２
浴温：４０〜６０℃
次いで表面処理した銅箔を３００℃で1時間加熱して再結晶処理を行った。
<Comparative Example 5>
The untreated copper foil used electrolytic copper foil B and was surface-treated under the following conditions.
In the surface treatment, plating was performed on the M surface to a thickness of 2 μm using a plating solution of surface treatment bath composition 8.
Electrolytic bath composition 8:
Cu = 787-2360 mmol / L
H 2 SO 4 = 205~2050mmol / L
Cl = 424-1410 mmol / L
Inorganic additive (iron sulfate heptahydrate) = 0.01 mmol / L
Electrolysis conditions:
Current density = 20-60A / dm2
Bath temperature: 40-60 ° C
Next, the surface-treated copper foil was recrystallized by heating at 300 ° C. for 1 hour.
＜比較例６＞
未処理銅箔は圧延銅箔を使用し、下記条件で表面処理した。
表面処理は、表面処理浴組成９のめっき液を使用してＭ面に２μｍの厚さにめっきを行った。
電解浴組成９：
Ｃｕ＝７８７〜２３６０ｍｍｏｌ／Ｌ
Ｈ2ＳＯ4＝２０５〜２０５０ｍｍｏｌ／Ｌ
Ｃｌ＝４２４〜１４１０ｍｍｏｌ／Ｌ
無機添加剤（硫酸鉄七水和物）＝０．０１ｍｍｏｌ／Ｌ
電解条件：
電流密度＝２０〜６０Ａ／ｄｍ２
浴温：４０〜６０℃
次いで表面処理した銅箔を３００℃で1時間加熱して再結晶処理を行った。
<Comparative Example 6>
Untreated copper foil was rolled copper foil and surface treated under the following conditions.
In the surface treatment, plating was performed on the M surface to a thickness of 2 μm using a plating solution having a surface treatment bath composition 9.
Electrolytic bath composition 9:
Cu = 787-2360 mmol / L
H 2 SO 4 = 205~2050mmol / L
Cl = 424-1410 mmol / L
Inorganic additive (iron sulfate heptahydrate) = 0.01 mmol / L
Electrolysis conditions:
Current density = 20-60 A / dm 2
Bath temperature: 40-60 ° C
Next, the surface-treated copper foil was recrystallized by heating at 300 ° C. for 1 hour.
＜粗化粒子を構成する銅の結晶粒径の測定＞
実施例１〜９、及び比較例１〜６で作成した再結晶加熱処理を行った銅箔の断面を走査型（ＳＥＭ）電子顕微鏡で撮影し、ランダムに１００個の粗化粒子を選別した。
選別した粗化粒子中に含まれる結晶粒の、長手方向（たとえば、図１（ハ）における矢印Ａ−Ａで示した元箔と垂直な方向、すなわち、粗大化した結晶粒の縦方向）の長さの平均値を算出した。結果を表１に記載した。
<Measurement of crystal grain size of copper constituting roughened particles >
The cross section of the copper foil which performed the recrystallization heat processing created in Examples 1-9 and Comparative Examples 1-6 was image | photographed with the scanning type | mold (SEM) electron microscope, and 100 roughening particles were selected at random.
The longitudinal direction of the crystal grains contained in the selected roughened particles (for example, the direction perpendicular to the original foil indicated by the arrow AA in FIG. 1 (c), that is, the longitudinal direction of the coarsened crystal grains) . The average length was calculated. The results are shown in Table 1.
＜耐屈曲性評価試験片の作成＞
実施例１〜９、及び比較例１〜６に示した再結晶加熱処理を行った銅箔を、ＪＩＳ Ｃ ５０１６−１９９４に記載されているライン／スペース＝１．５ｍｍ／1．０ｍｍの耐屈曲性試料を作成した。
<Creation of flexural resistance test specimen>
The copper foil subjected to the recrystallization heat treatment shown in Examples 1 to 9 and Comparative Examples 1 to 6 was subjected to bending resistance of line / space = 1.5 mm / 1.0 mm described in JIS C 5016-1994. Sex samples were prepared.
＜耐屈曲性試験（ＩＰＣ屈曲試験）＞
実施例１〜９、及び比較例１〜６に示した再結晶加熱処理を行った銅箔を耐屈曲性評価試験片（ＦＰＣ）とし、信越エンジニアリング株式会社製ＦＰＣ高速屈曲試験機ＳＥＫ−３１Ｂ２Ｓにセットし、ＩＰＣ規格ＴＭ−６５０に規定する条件（屈曲速度１５００回／分、ストローク長さ２０．０ｍｍ、曲率半径１．０ｍｍ）で耐屈曲性の測定を行った。測定は、回路抵抗を経時的に測定し、破断するまでの回数をカウントした。
結果を表１に記載した。
<Bend resistance test (IPC flex test)>
The copper foil subjected to the recrystallization heat treatment shown in Examples 1 to 9 and Comparative Examples 1 to 6 was used as a bending resistance evaluation test piece (FPC), and the FPC high-speed bending tester SEK-31B2S manufactured by Shin-Etsu Engineering Co., Ltd. was used. The bending resistance was measured under the conditions specified in IPC standard TM-650 (bending speed 1500 times / min, stroke length 20.0 mm , curvature radius 1.0 mm ). In the measurement, the circuit resistance was measured over time, and the number of times until breakage was counted.
The results are shown in Table 1.
＜０．２％耐力の測定＞
実施例１〜９、及び比較例１〜６に示した再結晶加熱処理を行った銅箔を、長さ６インチ、幅０．５インチの試験片に裁断し、引張試験機を用いて測定した。結果を表１に記載した。
<Measurement of 0.2% yield strength>
The copper foil subjected to the recrystallization heat treatment shown in Examples 1 to 9 and Comparative Examples 1 to 6 was cut into test pieces having a length of 6 inches and a width of 0.5 inches, and measured using a tensile tester. did. The results are shown in Table 1.
＜粗化粒子の均一付着性＞
実施例１〜９、及び比較例１〜６に示した銅箔表面を走査型電子顕微鏡で撮影し、図４に示す方法で粗化粒子間の平均間隔を算出し粗化粒子の均一付着性を測定した。
図４（イ）に示すように撮影した写真に対角線を引く。
次いで図４（ロ）に示すように対角線を２０μｍ間隔に区切り、その線にぶつかった、または接した粗化粒子の数及びその粒径を測定した。
測定した粗化粒子の平均サイズを算出した。
２０μｍから粗化粒子の粒径の合計値を引き、その値を（粗化粒子の数−１）で除し、平均間隔を算出した。
この手法で算出した粗化粒子間の平均間隔が０．５μｍ以下で、粗化粒子が隙間無く電着していると判断される条件を○とし、平均間隔が０．５μｍより大きく、粗化粒子の付着にムラがあると判断される条件を×と判定し、その結果を表１に併記した。
<Uniform adhesion of roughened particles>
The copper foil surface shown in Examples 1-9 and Comparative Examples 1-6 was image | photographed with the scanning electron microscope, the average space | interval between roughening particles was computed by the method shown in FIG. Was measured.
A diagonal line is drawn on the photograph taken as shown in FIG.
Next, as shown in FIG. 4B, the diagonal lines were divided at 20 μm intervals, and the number of coarse particles hitting or contacting the lines and the particle diameter thereof were measured.
The average size of the measured roughened particles was calculated.
The total value of the particle diameters of the roughened particles was subtracted from 20 μm, and the value was divided by (number of roughened particles−1) to calculate an average interval.
The average interval between the roughened particles calculated by this method is 0.5 μm or less, and the condition for determining that the roughened particles are electrodeposited without gaps is ○, and the average interval is larger than 0.5 μm. The condition for determining that there was unevenness in the adhesion of particles was determined as x, and the results are also shown in Table 1.
＜表面積比の測定方法＞
「表面積比」は上記のとおり、銅箔の表面に上記粗化処理を行い、その後、上記加熱処理したことより銅箔の結晶組織が粗大化して銅箔の表面積がどの程度変化したかを示す銅箔の表面積の変化の比率を言うが、ここでは、「表面積比」として、実施例１〜９、及び比較例１〜６に示した粗化処理と、３００℃で１時間の加熱処理を行った銅箔表面の５０μｍ×５０μｍ領域の表面積をレーザー顕微鏡で測定し、見かけの面積である２５００μｍ２で除すことで算出した。結果を表１に併記した。
<Method for measuring surface area ratio>
“Surface area ratio” indicates how much the surface area of the copper foil has changed due to the coarsening of the crystal structure of the copper foil as a result of performing the above roughening treatment on the surface of the copper foil and then the above heat treatment as described above. Although it says the ratio of the change of the surface area of copper foil, here, as "surface area ratio", the roughening process shown in Examples 1-9 and Comparative Examples 1-6 and the heat processing for 1 hour at 300 degreeC. The surface area of the 50 μm × 50 μm region of the copper foil surface was measured with a laser microscope and calculated by dividing by the apparent area of 2500 μm 2 . The results are also shown in Table 1.
＜ピール強度の測定方法＞
実施例１〜９、及び比較例１〜６に示した銅箔に、ニッカン工業株式会社製ニカフレックスＣＩＳＶ−２５２５（ポリイミドフィルム２５μｍ、接着剤厚さ２５μｍ）を、３００℃、４０ｋｇ／ｃｍ２、１時間の条件でラミネートし、ラミネート面にＦＲ４基材を貼り付けた。基材に貼り付けた試料をエッチングマシンに挿入し、１０ｍｍ幅の試験片を作成した。その後、ピール試験機で銅箔を９０度方向に４０ｍｍ引き剥がし、その間の平均ピール強度を測定した。
<Measurement method of peel strength>
To the copper foils shown in Examples 1 to 9 and Comparative Examples 1 to 6, Nikaflex CISV-2525 (polyimide film 25 μm, adhesive thickness 25 μm) manufactured by Nikkan Kogyo Co., Ltd., 300 ° C., 40 kg / cm 2 , Lamination was performed for 1 hour, and an FR4 substrate was attached to the laminated surface. The sample affixed to the base material was inserted into an etching machine, and a 10 mm wide test piece was created. Thereafter, the copper foil was peeled off by 40 mm in the 90-degree direction with a peel tester, and the average peel strength was measured.
表１に示すように、本発明の実施形態である実施例１〜９は、再結晶処理することで粗化粒子結晶と銅箔本体結晶組織とが一体化して粗化処理後の粗化粒子を構成する銅の結晶粒径が大きくなっており、屈曲回数も１１，０００回を超える耐屈曲性を示している。また、３００℃×１時間加熱した後の０．２％耐力も１６０Ｎ／ｍｍ２以下であり、粗化粒
子は均一に付着している。従ってかかる表面粗化処理銅箔は絶縁フィルムとの接着性に優れ、絶縁フィルムとの接着後の耐屈曲性に優れる回路基板を提供することができる。
As shown in Table 1, Examples 1 to 9, which are embodiments of the present invention, are obtained by recrystallizing the roughened particle crystal and the copper foil main body crystal structure into a unified roughened particle after the roughening treatment. The crystal grain size of copper constituting the material is large, and the bending resistance exceeds 11,000 times. Moreover, the 0.2% yield strength after heating at 300 ° C. for 1 hour is 160 N / mm 2 or less, and the roughened particles are uniformly attached. Therefore, the surface roughened copper foil is excellent in adhesion to the insulating film, and can provide a circuit board having excellent bending resistance after adhesion to the insulating film.
一方比較例１は粗化処理電解液に添加剤を添加しなかったために粗化粒子の均一性に劣り、満足する結果を得ることができなかった。
比較例２〜６には添加剤として硫酸鉄七水和物を用いたが、粗化粒子の再結晶が不足し、従って耐屈曲性が劣り、満足する銅箔を得ることができなかった。
On the other hand, Comparative Example 1 was inferior in uniformity of the roughened particles because no additive was added to the roughened electrolytic solution, and a satisfactory result could not be obtained.
In Comparative Examples 2 to 6, iron sulfate heptahydrate was used as an additive, but the recrystallization of the roughened particles was insufficient, and therefore the bending resistance was poor, and a satisfactory copper foil could not be obtained.
表面積比は特にポリイミドとの接着強度（ピール強度）に影響する。未処理銅箔表面に粗化処理を施し、加熱処理して粗化処理面を再結晶することで表面積比とピール強度との変化を検討したが、表１に示すように表面積比が１．５〜３．５の範囲（実質的には１．１〜５．０の範囲）では表面積比が上がるに従ってピール強度も上昇する傾向を示し、比較例との対比においても、粗化粒子の結晶粒径によりピール強度に影響がでないことを確認できた。 The surface area ratio particularly affects the adhesive strength (peel strength) with polyimide. The surface area ratio and the peel strength were examined by subjecting the untreated copper foil surface to a roughening treatment, heat treatment, and recrystallization of the roughened surface. In the range of 5 to 3.5 (substantially in the range of 1.1 to 5.0), the peel strength tends to increase as the surface area ratio increases. It was confirmed that the peel strength was not affected by the particle size.
１ 銅箔本体
２ 粗化粒子
1
Claims (6)
ここで、表面積比とは、銅箔の表面に上記粗化処理を行い、その後、上記加熱処理したことより銅箔の結晶組織が粗大化して銅箔の表面積がどの程度変化したかを示す銅箔の表面積の変化の比率を言う。 A copper foil having a surface-roughened layer on at least one surface of an untreated copper foil, the copper foil being heated at 300 ° C. for 1 hour, and the line / space = 1 in FIG. 4 of JIS C 5016-1994 = 1 After processing into a circuit of .5mm x 1.0mm, IPC bending test (conforms to IPC standard TM-650) is performed under the conditions of bending speed 1500 times / minute, stroke length 20.0mm, curvature radius 1.0mm. As a result, the average number of crystal grains of the copper constituting the roughened particles after the number of flexing resistances is 11,000 times or more and the copper foil provided with the surface roughened layer is heated at 300 ° C. for 1 hour. A surface-roughened copper foil having a diameter of 0.5 μm or more and a surface area ratio of 1.1 to 5.0.
Here, the surface area ratio is the copper that indicates how much the surface area of the copper foil has changed due to the coarsening of the crystal structure of the copper foil by performing the above roughening treatment on the surface of the copper foil and then the above heat treatment. The ratio of the change in the surface area of the foil.
前記未処理銅箔の少なくとも片面を、チオ尿素、エチレンチオ尿素、または、チオセミカルバジドが０．００１ｍｍｏｌ（ミリモル）／Ｌ（リットル）〜０．１ｍｍｏｌ／Ｌ添加された電解液で表面粗化処理し、少なくとも片面に表面粗化処理層を有する銅箔を製造する表面粗化処理銅箔の製造方法。 It is a manufacturing method of the surface roughening processing copper foil in any one of Claims 1-3,
At least one surface of the untreated copper foil is subjected to a surface roughening treatment with an electrolyte containing 0.001 mmol (mmol) / L (liter) to 0.1 mmol / L of thiourea, ethylenethiourea, or thiosemicarbazide, The manufacturing method of the surface roughening process copper foil which manufactures the copper foil which has a surface roughening process layer at least on one side.
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| JPH06237078A (en) * | 1993-02-09 | 1994-08-23 | Nikko Guurudo Foil Kk | Manufacture of copper foil for printed circuit |
| JP2005340382A (en) * | 2004-05-25 | 2005-12-08 | Mitsui Mining & Smelting Co Ltd | Flexible printed wiring board and method for manufacturing same |
| JP4781930B2 (en) * | 2005-07-27 | 2011-09-28 | 新日鐵化学株式会社 | Method for producing highly flexible flexible copper clad laminate |
| JP5136768B2 (en) * | 2008-01-21 | 2013-02-06 | 日立電線株式会社 | Copper foil for circuit boards |
| JP5136383B2 (en) * | 2008-12-15 | 2013-02-06 | 日立電線株式会社 | Rolled copper foil for printed wiring boards |
| JP5400447B2 (en) * | 2009-03-31 | 2014-01-29 | 三井金属鉱業株式会社 | Roughened copper foil, method for producing roughened copper foil, and copper-clad laminate |
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