WO2012070471A1 - Rolled copper foil for flexible printed wiring board, copper-clad laminated board, flexible wiring board, and electronic device - Google Patents

Rolled copper foil for flexible printed wiring board, copper-clad laminated board, flexible wiring board, and electronic device Download PDF

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Publication number
WO2012070471A1
WO2012070471A1 PCT/JP2011/076581 JP2011076581W WO2012070471A1 WO 2012070471 A1 WO2012070471 A1 WO 2012070471A1 JP 2011076581 W JP2011076581 W JP 2011076581W WO 2012070471 A1 WO2012070471 A1 WO 2012070471A1
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Prior art keywords
flexible printed
printed wiring
wiring board
copper foil
board
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PCT/JP2011/076581
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French (fr)
Japanese (ja)
Inventor
岡野　朋樹
和樹 冠
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Jx日鉱日石金属株式会社
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Publication of WO2012070471A1 publication Critical patent/WO2012070471A1/en

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/09—Use of materials for the conductive, e.g. metallic pattern
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/03—Use of materials for the substrate
    • H05K1/0393—Flexible materials
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/03—Conductive materials
    • H05K2201/0332—Structure of the conductor
    • H05K2201/0335—Layered conductors or foils
    • H05K2201/0355—Metal foils

Definitions

  • the present invention relates to a rolled copper foil for a flexible printed wiring board, a copper-clad laminate using the same, a flexible printed wiring board, and an electronic device.
  • An electronic device is usually composed of a plurality of electronic boards, and a printed wiring board that electrically connects these electronic boards is provided between the electronic boards.
  • a printed wiring board usually includes an insulating substrate and copper wiring formed on the surface of the substrate.
  • a printed wiring board is often required to have flexibility or the like, and a flexible printed wiring board is generally used.
  • the properties required for the flexible printed circuit board good bending properties typified by MIT flex resistance, and has high cycle flexibility typified by IPC flexibility, conventionally, with such properties Cu- Resin substrate laminates have been developed (Patent Documents 1 and 2).
  • a copper foil is formed on a resin substrate. At this time, the surface of the copper foil is often roughened in order to improve adhesion to the resin substrate.
  • a copper foil having a smooth surface and excellent adhesion to a resin substrate has been proposed, and a fine pattern of wiring can be formed without using a metalizing method. If a fine pattern can be formed in this way, a rolled copper foil can be used with COF (Chip On Film) or the like (Patent Documents 3 and 4).
  • a flexible printed wiring board is provided between two substrates as described above in an electronic device and electrically connects both.
  • these two substrates have the same linear thermal expansion coefficient, there is a problem.
  • the substrate has a difference in coefficient of linear thermal expansion, stress concentration occurs on the flexible printed wiring board due to turning on and off the power supply of the electronic device, temperature change at the place of use, and the like.
  • the flexible printed wiring board is designed in consideration of good bendability represented by MIT bendability and high cycle bendability represented by IPC bendability. Such stress concentrations are not planned and are not designed to withstand. For this reason, cracks due to the stress concentration occur in the wiring of the flexible printed wiring board due to long-term use of the electronic device, which causes the failure of the electronic device.
  • the present invention when used as a wiring of a flexible printed wiring board, a rolled copper foil that does not crack in wiring even after long-term use, and a copper-clad laminate, a flexible printed wiring board using the rolled copper foil, and It is an object to provide an electronic device.
  • the present invention completed based on the above knowledge is used as a wiring of a flexible printed wiring board that electrically connects a first board and a second board having a linear thermal expansion coefficient difference of 1.2 times or more.
  • a temperature change of ⁇ 10 ° C. to + 90 ° C. 1000 times cracks do not occur in the wiring.
  • the flexible It is a rolled copper foil for flexible printed wiring boards in which cracks do not occur in the wiring even when the temperature change of ⁇ 10 ° C. to + 90 ° C. is repeated 1000 times.
  • the distance between the first substrate and the second substrate is 10 mm or less, and at least the first substrate and the second substrate.
  • the length of the end portion of the substrate including the region where the flexible printed wiring board is provided is 200 mm or more.
  • the area of the contact surface between the base film of the flexible printed wiring board and the copper foil is that of the flexible printed wiring board. Less than 50% of the surface area.
  • the minimum value of the wiring width of the flexible printed wiring board is 25 ⁇ m or less.
  • the copper foil has a total of 50 to 1000 ⁇ g / Cr on the base film side surface of the flexible printed wiring board. dm 2 is adhered, and the surface roughness (Ra) on the surface is Ra ⁇ 0.2 ⁇ m.
  • the copper foil includes Cr and Ni as essential components on the base film side surface of the flexible printed wiring board, and Sn.
  • rolled copper foil for flexible printed wiring board Pd, Ag, Au, Cr, Ni, Sn are formed on the surface of the copper foil opposite to the surface to which Cr and Ni are adhered. And one or more selected from the group consisting of V and V are attached in a total of 50 to 1000 ⁇ g / dm 2 .
  • the adhering element essentially contains Pd.
  • the copper foil is formed of tough pitch copper or oxygen-free copper.
  • the copper foil Ag the tough pitch copper or oxygen-free copper, Sn, Cr, Zr, Fe, As, Sb, Bi, It is formed of a copper alloy to which at least one or two or more of Se, Te, and Pb are added in a total of 2000 ppm or less (excluding 0 ppm).
  • the present invention is a copper clad laminate provided with the copper foil according to the present invention.
  • the present invention is a flexible printed wiring board made of the copper clad laminate according to the present invention.
  • FIG. 1 Another aspect of the present invention is an electronic device including the flexible printed wiring board according to the present invention and a first substrate and a second substrate electrically connected by the flexible printed wiring board.
  • a rolled copper foil that does not crack in wiring even after long-term use and a copper-clad laminate
  • a flexible printed wiring board using the rolled copper foil and An electronic device can be provided.
  • the copper alloy foil based on tough pitch copper and oxygen-free copper is a total of at least one or more of Ag, Sn, Cr, Zr, Fe, As, Sb, Bi, Se, Te and Pb. And 2000 ppm or less (excluding 0 ppm), preferably 5 ppm to 1500 ppm, more preferably 20 ppm to 1000 ppm.
  • ppm means mass ppm.
  • the copper alloy foil is also included.
  • “tough pitch copper and oxygen-free copper” copper alloy based on tough pitch copper and oxygen-free copper is used. Includes foil.
  • the thickness of the copper foil that can be used in the present invention is preferably 5 to 18 ⁇ m.
  • the thickness of the copper foil is less than 5 ⁇ m, the handling of the copper foil is deteriorated, and when it is more than 18 ⁇ m, the fine etching property is deteriorated.
  • a flexible printed wiring board according to the present invention includes an insulating substrate and a wiring pattern formed on the surface of the insulating substrate.
  • the insulating substrate is not particularly limited as long as it has good bendability and bendability applicable to a flexible printed wiring board.
  • a polyimide film or a liquid crystal polymer film can be used.
  • the wiring pattern is formed using the above-mentioned rolled copper foil for flexible printed wiring boards.
  • the shape of the wiring pattern is not particularly limited, and any shape may be used.
  • the flexible printed wiring board which concerns on this invention Since the flexible printed wiring board which concerns on this invention is formed using the above rolled copper foil for flexible printed wiring boards, it has the following characteristics. That is, with respect to the first printed circuit board and the second printed circuit board to which the flexible printed wiring board is electrically connected, when both boards have a difference in linear thermal expansion coefficient of 1.2 times or more, the flexible printed wiring board Even if the temperature change from ⁇ 10 ° C. to + 90 ° C. is repeated 1000 times, the wiring does not crack. Furthermore, even when the two substrates have a difference in linear thermal expansion coefficient of 1.5 times or more, the wiring is cracked even if the temperature change of -10 ° C to + 90 ° C is repeated 1000 times with respect to the flexible printed wiring board Does not occur.
  • the difference in linear thermal expansion coefficient between the first substrate and the second substrate is 1.5 times or more, it cannot withstand the stress concentration caused by the difference in expansion between the two substrates due to temperature change, and the flexible printed wiring board There is a high possibility of cracks in the wiring.
  • the difference between the linear expansion coefficients of the first substrate and the second substrate is 1.2 times or more, there is a possibility that cracks may occur in the wiring of the flexible printed wiring board.
  • the present invention the occurrence of cracks in the wiring is well suppressed even in such a state.
  • the temperature change from ⁇ 10 ° C. to + 90 ° C. is repeated 1000 times with respect to the flexible printed wiring board means that, as shown in FIG. Holding at 90 ° C. and ⁇ 10 ° C. for 30 minutes means repeating this 1000 times as one cycle.
  • the transfer between a high temperature tank and a low temperature tank is performed within 1 minute.
  • Other conditions are performed according to JIS C0025.
  • FIG. 2 shows a region (connection portion) where the flexible printed wiring board is provided in the first substrate or the second substrate, and a substrate end including the region.
  • the linear thermal expansion coefficient is an expansion coefficient in a direction parallel to the extending direction of the substrate end, and a value at room temperature is used.
  • the flexible printed wiring board according to the present invention is a flexible printed wiring board that electrically connects a first board and a second board having a linear thermal expansion coefficient difference of 1.2 times or more.
  • the crack does not occur in the wiring even if the temperature change of ⁇ 65 ° C. to + 100 ° C. is repeated 100 times with respect to the flexible printed wiring board.
  • the two substrates have a difference in linear thermal expansion coefficient of 1.5 times or more, the wiring is cracked even if the temperature change from -65 ° C to + 100 ° C is repeated 100 times with respect to the flexible printed wiring board Does not occur.
  • the flexible printed wiring board according to the present invention is a flexible printed wiring board that electrically connects a first board and a second board having a linear thermal expansion coefficient difference of 1.2 times or more.
  • a wiring When used as a wiring, no cracks occur in the wiring even if the temperature change of ⁇ 65 ° C. to + 125 ° C. is repeated 100 times with respect to the flexible printed wiring board.
  • both boards have a difference in linear thermal expansion coefficient of 1.5 times or more, the wiring is cracked even if the temperature change of -65 ° C to + 125 ° C is repeated 100 times with respect to the flexible printed wiring board. Does not occur.
  • the distance between the substrates of the first substrate and the second substrate is 10 mm or less, and at least one of the first substrate and the second substrate includes a region where the flexible printed wiring board according to the present invention is provided.
  • the length may be 200 mm or more.
  • FIG. 2 shows a region (connection portion) where the flexible printed wiring board is provided in the first substrate or the second substrate, and a substrate end including the region. The longer the lengths of the substrate end portions of the first substrate and the second substrate including the region where the flexible printed wiring board is provided, the greater the concentration of stress applied to the flexible printed wiring board.
  • the length of the substrate end portion of the first substrate or the second substrate including the region where the flexible printed wiring board is provided is 200 mm or more.
  • the present invention the occurrence of cracks in the wiring is well suppressed even in such a state.
  • the area of the contact surface between the base film of the flexible printed wiring board and the copper foil may be less than 50% of the surface area of the flexible printed wiring board.
  • the wiring pattern of the rolled copper foil has the function of fixing the flexible printed wiring board and improving the stress resistance characteristics. Therefore, conversely, if the surface area of the rolled copper foil for flexible printed wiring board in the flexible printed wiring board is reduced, the stress resistance characteristic of the flexible printed wiring board is lowered accordingly.
  • the surface area of the rolled copper foil for a flexible printed wiring board is less than 50% of the surface area of the flexible printed wiring board, the flexible printed wiring board cannot withstand the stress concentration caused by the difference in expansion between the two substrates due to temperature changes. There is a high possibility that cracks will occur in the wiring. On the other hand, in the present invention, the occurrence of cracks in the wiring is well suppressed even in such a state.
  • each wiring width constituting the wiring pattern of the flexible printed wiring board may be 25 ⁇ m or less.
  • the minimum value of the wiring width is 25 ⁇ m or less, the stress concentration generated by the difference in expansion between the two substrates due to temperature change cannot be withstood, and there is a high possibility that a crack will occur.
  • the present invention the occurrence of cracks in the wiring is well suppressed even in such a state.
  • a total of 50 to 1000 ⁇ g / dm 2 of Cr and Ni may be adhered to the base film side surface of the flexible printed wiring board. According to such a structure, it has the effect that the adhesiveness and heat resistance of copper foil improve.
  • the adhesion amount of Cr and Ni is less than 50 ⁇ g / dm 2 in total, the adhesion and heat resistance of the copper foil are poor.
  • the etching property becomes poor.
  • the surface roughness (Ra) on the surface may be Ra ⁇ 0.2 ⁇ m. According to such a structure, it has the effect that the fine etching property of copper foil improves.
  • the rolled copper foil according to the present invention is selected from the group consisting of Cr and Ni as essential components, Sn, Co, V, Ti, Zn, Mn and Fe on the base film side surface of the flexible printed wiring board.
  • One or two or more of them may be attached in a total of 50 to 1000 ⁇ g / dm 2 . According to such a configuration, there is an effect that adhesion, heat resistance or etching is improved. When the amount of adhesion is less than 50 ⁇ g / dm 2 in total, the adhesion, heat resistance or etching becomes poor. Further, if the total amount of adhesion is more than 1000 ⁇ g / dm 2 , the etching property becomes poor.
  • One type or two or more types selected from the group consisting of Pd, Ag, Au, Cr, Ni, Sn and V are added to the surface opposite to the surface to which Cr and Ni of the rolled copper foil according to the present invention are attached. 50 to 1000 ⁇ g / dm 2 may be adhered. According to such a configuration, the etching property is improved, and there is an effect that a fine pitch circuit can be formed. Furthermore, heat resistance becomes favorable. When the adhesion amount is less than 50 ⁇ g / dm 2 in total, the etching property and heat resistance are poor. Further, if the total amount of adhesion is more than 1000 ⁇ g / dm 2 , the etching property becomes poor. For the above effect, it is more preferable that Pd is contained as an essential element in the adhering element.
  • a flexible printed wiring board can be manufactured according to a conventional method using the rolled copper foil. Below, the manufacture example of a flexible printed wiring board is shown. First, a copper clad laminate is manufactured by laminating a rolled copper foil and an insulating substrate such as a polyimide film or a liquid crystal polymer film having good flexibility and foldability.
  • thermoplastic polyimide adhesive is applied to the thermosetting polyimide film and dried, and then laminated with a copper foil and thermocompression bonded.
  • pressure bonding method there are a method of vacuum hot pressing and a method of laminating with a heat roll.
  • a copper-clad laminate is produced by coating, drying and curing a polyimide precursor on a copper foil.
  • a method well known to those skilled in the art may be used. For example, an etching resist is applied only to a necessary portion as a wiring pattern on a copper foil surface of a copper clad laminate, and unnecessary copper foil is removed by spraying an etching solution onto the copper foil surface to form a circuit pattern. Next, a flexible printed wiring board is produced by peeling and removing the etching resist to expose the wiring pattern.
  • the electronic devices can be manufactured by providing this flexible printed wiring board between two electronic boards and electrically connecting them.
  • the electronic devices is not particularly limited, for example, include a liquid crystal display, a car navigation, mobile phone, game machine, CD player, digital camera, TV, DVD player, electronic organizers, electronic dictionaries, calculators, video cameras, printers, etc. It is done.
  • Examples 1 to 56, 57, 58, 61, 65, 66 are based on tough pitch copper ingots and oxygen-free copper, and are based on at least Ag, Sn, Cr, Zr, Fe, As, Sb, Bi, Se, Te, and Pb.
  • An ingot produced by adding one or more kinds is processed into a plate having a thickness of 10 mm by hot rolling, the oxide is removed by surface cutting, and then cold rolling, annealing and pickling are repeated.
  • a copper foil was produced by processing to the thickness described in (3) to (3), and surface treatment was applied to the surface of the copper foil by sputtering.
  • Examples 1 to 32, 63, 64, 66, and 68 were obtained by applying a 18.5 ⁇ m thick thermoplastic PI adhesive to Kapton EN (registered trademark) and drying a 38.5 ⁇ m thick resin layer on a copper foil.
  • a copper clad laminate was produced by vacuum hot pressing.
  • Examples 33 to 62, 65, and 67 were prepared by applying polyimide varnish (U varnish S manufactured by Ube Industries Co., Ltd.) to copper foil, drying, and curing to form a 37.5 ⁇ m resin layer to produce a copper clad laminate. did.
  • a copper foil wiring pattern was formed by etching so that the wiring width and area ratio shown in Tables 1 to 3 were obtained.
  • each wiring was formed so that the width
  • the flexible printed wiring board was produced by the above procedure. At this time, it was confirmed that the adhesion strength between the copper foil and the resin layer was 0.7 kN / m or more, and the copper foil was controlled not to peel during the test. Subsequently, as shown in Tables 1 to 3 and FIGS. 3 to 4, a first substrate and a second substrate formed using a rigid substrate such as FR4 and / or a glass substrate are prepared, and a predetermined inter-substrate distance is prepared. The flexible printed wiring board was pressure-bonded with an anisotropic conductive adhesive film (ACF).
  • ACF anisotropic conductive adhesive film
  • the 3 to 4 show various patterns (patterns 1 to 7) of the connection form between the first substrate and the second substrate and the flexible printed wiring board formed therebetween, respectively.
  • the patterns 1 to 3, 6, and 7 are formed in a circuit that is parallel and has a constant L (line) / S (space). Moreover, the circuit is not formed in both side etch 0.5mm.
  • the length of the wiring boards of patterns 2 and 3 is 35 mm.
  • the circuits are formed in a radial pattern. Since the circuit widths of the patterns 4 and 5 are not changed, the L / S differs depending on the location so that the space becomes wider in the direction in which the circuit expands.
  • L / S is a circuit with an equal interval.
  • neither side edge of 0.5 mm forms a circuit.
  • the first substrate and the second substrate expand in the direction of the linear thermal expansion coefficient (the direction of the arrow) shown in each drawing.
  • ⁇ 10 ° C. to + 90 ° C., or ⁇ 65 to A temperature change of + 100 ° C. or ⁇ 65 to + 125 ° C. was repeatedly applied, and the number of repetitions when a crack occurred in the wiring of the flexible printed wiring board was measured.
  • Comparative example As Comparative Examples 1 to 16 and 18, Kapton EN (registered trademark) manufactured by Toray DuPont Co., Ltd. is used as a resin layer, and metal layers Cr, Ni, and Cu are sputtered to improve adhesion and electrodeposit Cu in a later step. After that, a copper layer was formed by electrodeposition to produce a copper clad laminate. The thickness of the resin layer was 37.5 ⁇ m. Further, as Comparative Example 17, a 38.5 ⁇ m thick resin layer formed by applying 1 ⁇ m of thermoplastic PI adhesive to Kapton EN and drying on electrolytic copper foil NA-VLP manufactured by Mitsui Mining & Mining Co., Ltd. was laminated on the copper foil.
  • a copper clad laminate was produced by vacuum hot pressing.
  • a copper foil wiring pattern was formed by etching so that the wiring width and area ratio shown in Table 7 were obtained.
  • each wiring was formed so that the width
  • the flexible printed wiring board was produced by the above procedure. At this time, it was confirmed that the adhesion strength between the copper foil and the resin layer was 0.7 kN / m or more, and the copper foil was controlled not to peel during the test.
  • a first substrate and a second substrate formed using a rigid substrate such as FR4 and / or a glass substrate are prepared, and the distance between the substrates is set to 6 mm.
  • the wiring board was pressure-bonded with an anisotropic conductive adhesive film (ACF). Subsequently, for the sample made of the first substrate, the second substrate, and the flexible printed wiring board that electrically connects them, manufactured as described above, ⁇ 10 ° C. to + 90 ° C., or ⁇ 65 to A temperature change of + 100 ° C. or ⁇ 65 to + 125 ° C. was repeatedly given, and the number of repetitions when a crack occurred in the wiring of the flexible printed wiring board was measured.
  • the occurrence of cracks was determined as follows.
  • a constant current (0.01 to 0.1 mA) is passed through the wiring of the flexible printed wiring board, a voltage value necessary to pass the current is measured, and the wiring resistance of the flexible printed wiring board is calculated from the measured voltage value. The value was calculated. When the calculated resistance value was 500% or more of the initial value, it was determined that a crack occurred. Further, the arithmetic average roughness Ra ( ⁇ m) based on JIS-B0601 of the surface (1) of the copper foil on the base film side was measured. A contact roughness meter (manufactured by Kosaka Laboratory, trade name “SE-3400”) was used to measure the arithmetic average roughness Ra ( ⁇ m). Tables 1 to 7 show the test conditions and measurement results.

Abstract

Provided is a rolled copper foil with which cracks do not arise in wiring even when used for a long time in wiring of a flexible printed wiring board. Also provided are a copper-clad laminated board using the same, a flexible printed wiring board, and an electronic device. When used for wiring in a flexible printed wiring board that electrically connects a first substrate and second substrate for which the difference in coefficients of linear thermal expansion is 1.2 times or greater, the rolled copper foil for a flexible printed wiring board does not give rise to cracks in the wiring even when the temperature of the flexible printed wiring board is varied -10°C - 90°C 1000 times.

Description

フレキシブルプリント配線板用圧延銅箔、銅張積層板、フレキシブルプリント配線板及び電子機器Rolled copper foil for flexible printed wiring boards, copper-clad laminates, flexible printed wiring boards, and electronic equipment
　本発明は、フレキシブルプリント配線板用圧延銅箔、及び、それを用いた銅張積層板、フレキシブルプリント配線板及び電子機器に関する。 The present invention relates to a rolled copper foil for a flexible printed wiring board, a copper-clad laminate using the same, a flexible printed wiring board, and an electronic device.
　電子機器は、通常複数の電子基板で構成されており、これら電子基板同士を電気的に接続するプリント配線板が電子基板間に設けられている。プリント配線板は、通常、絶縁基板と、該基板表面に形成された銅製の配線とを備えている。プリント配線板には屈曲性等が求められる場合が多く、一般的に、フレキシブルプリント配線板が用いられる。フレキシブルプリント配線板に求められる特性としては、ＭＩＴ屈曲性に代表される良好な折り曲げ性、及び、ＩＰＣ屈曲性に代表される高サイクル屈曲性があり、従来、このような特性を備えたＣｕ－樹脂基板積層体が開発されている（特許文献１、２）。 An electronic device is usually composed of a plurality of electronic boards, and a printed wiring board that electrically connects these electronic boards is provided between the electronic boards. A printed wiring board usually includes an insulating substrate and copper wiring formed on the surface of the substrate. A printed wiring board is often required to have flexibility or the like, and a flexible printed wiring board is generally used. The properties required for the flexible printed circuit board, good bending properties typified by MIT flex resistance, and has high cycle flexibility typified by IPC flexibility, conventionally, with such properties Cu- Resin substrate laminates have been developed (Patent Documents 1 and 2).
　フレキシブルプリント配線板の作製において、樹脂基板上に銅箔を形成するが、このとき、樹脂基板との密着性を上げるために銅箔表面に粗化処理を行うことが多かった。近年、平滑な表面を有しながら樹脂基板との密着性に優れる銅箔が提案されており、メタライジング法によらなくても配線のファインパターンを形成することが可能となっている。このようにファインパターンを形成することができれば、ＣＯＦ（Chip On Film）等で圧延銅箔を使用することができる（特許文献３、４）。 In the production of a flexible printed wiring board, a copper foil is formed on a resin substrate. At this time, the surface of the copper foil is often roughened in order to improve adhesion to the resin substrate. In recent years, a copper foil having a smooth surface and excellent adhesion to a resin substrate has been proposed, and a fine pattern of wiring can be formed without using a metalizing method. If a fine pattern can be formed in this way, a rolled copper foil can be used with COF (Chip On Film) or the like (Patent Documents 3 and 4).
特開２０１０－１００８８７号公報Japanese Unexamined Patent Publication No. 2010-100787 特開２００９－１１１２０３号公報JP 2009-111203 A 特開２００７－２０７８１２号公報JP 2007-207812 A 特開２００５－４８２６９号公報JP 2005-48269 A
　フレキシブルプリント配線板は、電子機器において上述のように２つの基板間に設けられて両者を電気的に接続しているが、この２つの基板が同じ線熱膨張係数を有するものであれば問題とはならないが、線熱膨張係数に差がある基板であれば、電子機器の電源のオンとオフや、使用場所の気温変化等によってフレキシブルプリント配線板に応力集中が生じる。これに対し、フレキシブルプリント配線板は、ＭＩＴ屈曲性に代表される良好な折り曲げ性、及び、ＩＰＣ屈曲性に代表される高サイクル屈曲性については考慮されて設計されているが、通常、上述のような応力集中は予定されておらず、それに耐え得るように設計されていない。このため、電子機器の長期の使用等によって、フレキシブルプリント配線板の配線に上記応力集中によるクラックが発生し、電子機器の故障の原因となっている。 A flexible printed wiring board is provided between two substrates as described above in an electronic device and electrically connects both. However, if these two substrates have the same linear thermal expansion coefficient, there is a problem. However, if the substrate has a difference in coefficient of linear thermal expansion, stress concentration occurs on the flexible printed wiring board due to turning on and off the power supply of the electronic device, temperature change at the place of use, and the like. On the other hand, the flexible printed wiring board is designed in consideration of good bendability represented by MIT bendability and high cycle bendability represented by IPC bendability. Such stress concentrations are not planned and are not designed to withstand. For this reason, cracks due to the stress concentration occur in the wiring of the flexible printed wiring board due to long-term use of the electronic device, which causes the failure of the electronic device.
　そこで、本発明は、フレキシブルプリント配線板の配線として用いられたときに、長期の使用によっても配線にクラックが発生しない圧延銅箔、及び、それを用いた銅張積層板、フレキシブルプリント配線板及び電子機器を提供することを課題とする。 Therefore, the present invention, when used as a wiring of a flexible printed wiring board, a rolled copper foil that does not crack in wiring even after long-term use, and a copper-clad laminate, a flexible printed wiring board using the rolled copper foil, and It is an object to provide an electronic device.
　本発明者らは、鋭意検討の結果、フレキシブルプリント配線板の配線として特定の圧延銅箔を用いることで、長期間使用してもフレキシブルプリント配線板の配線におけるクラックの発生を良好に抑制することができることを見出した。 As a result of intensive studies, the inventors have successfully suppressed the occurrence of cracks in the wiring of the flexible printed wiring board even when used for a long time by using a specific rolled copper foil as the wiring of the flexible printed wiring board. I found out that I can.
　以上の知見を基礎として完成した本発明は一側面において、線熱膨張係数が１．２倍以上差のある第１基板と第２基板とを電気的に接続するフレキシブルプリント配線板の配線として用いたときに、前記フレキシブルプリント配線板を－１０℃～＋９０℃の温度変化を１０００回繰り返しても前記配線にクラックが発生しないフレキシブルプリント配線板用圧延銅箔である。 In one aspect, the present invention completed based on the above knowledge is used as a wiring of a flexible printed wiring board that electrically connects a first board and a second board having a linear thermal expansion coefficient difference of 1.2 times or more. When the flexible printed wiring board is subjected to a temperature change of −10 ° C. to + 90 ° C. 1000 times, cracks do not occur in the wiring.
　本発明は別の一側面において、線熱膨張係数が１．５倍以上差のある第１基板と第２基板とを電気的に接続するフレキシブルプリント配線板の配線として用いたときに、前記フレキシブルプリント配線板を－１０℃～＋９０℃の温度変化を１０００回繰り返しても前記配線にクラックが発生しないフレキシブルプリント配線板用圧延銅箔である。 In another aspect of the present invention, when the first and second substrates having a linear thermal expansion coefficient difference of 1.5 times or more are used as the wiring of the flexible printed wiring board, the flexible It is a rolled copper foil for flexible printed wiring boards in which cracks do not occur in the wiring even when the temperature change of −10 ° C. to + 90 ° C. is repeated 1000 times.
　本発明は更に別の一側面において、線熱膨張係数が１．２倍以上差のある第１基板と第２基板とを電気的に接続するフレキシブルプリント配線板の配線として用いたときに、前記フレキシブルプリント配線板を－６５℃～＋１００℃の温度変化を１００回繰り返しても前記配線にクラックが発生しないフレキシブルプリント配線板用圧延銅箔である。 In still another aspect of the present invention, when used as a wiring of a flexible printed wiring board that electrically connects a first substrate and a second substrate having a linear thermal expansion coefficient difference of 1.2 times or more, It is a rolled copper foil for flexible printed wiring boards in which cracks do not occur in the wiring even when the temperature change of −65 ° C. to + 100 ° C. is repeated 100 times.
　本発明は更に別の一側面において、線熱膨張係数が１．５倍以上差のある第１基板と第２基板とを電気的に接続するフレキシブルプリント配線板の配線として用いたときに、前記フレキシブルプリント配線板を－６５℃～＋１００℃の温度変化を１００回繰り返しても前記配線にクラックが発生しないフレキシブルプリント配線板用圧延銅箔である。 In still another aspect of the present invention, when used as a wiring of a flexible printed wiring board that electrically connects a first substrate and a second substrate having a linear thermal expansion coefficient difference of 1.5 times or more, It is a rolled copper foil for flexible printed wiring boards in which cracks do not occur in the wiring even when the temperature change of −65 ° C. to + 100 ° C. is repeated 100 times.
　本発明は更に別の一側面において、線熱膨張係数が１．２倍以上差のある第１基板と第２基板とを電気的に接続するフレキシブルプリント配線板の配線として用いたときに、前記フレキシブルプリント配線板を－６５℃～＋１２５℃の温度変化を１００回繰り返しても前記配線にクラックが発生しないフレキシブルプリント配線板用圧延銅箔である。 In still another aspect of the present invention, when used as a wiring of a flexible printed wiring board that electrically connects a first substrate and a second substrate having a linear thermal expansion coefficient difference of 1.2 times or more, This is a rolled copper foil for flexible printed wiring boards in which cracks do not occur in the wiring even when the temperature change of −65 ° C. to + 125 ° C. is repeated 100 times for the flexible printed wiring board.
　本発明は更に別の一側面において、線熱膨張係数が１．５倍以上差のある第１基板と第２基板とを電気的に接続するフレキシブルプリント配線板の配線として用いたときに、前記フレキシブルプリント配線板を－６５℃～＋１２５℃の温度変化を１００回繰り返しても前記配線にクラックが発生しないフレキシブルプリント配線板用圧延銅箔である。 In still another aspect of the present invention, when used as a wiring of a flexible printed wiring board that electrically connects a first substrate and a second substrate having a linear thermal expansion coefficient difference of 1.5 times or more, This is a rolled copper foil for flexible printed wiring boards in which cracks do not occur in the wiring even when the temperature change of −65 ° C. to + 125 ° C. is repeated 100 times for the flexible printed wiring board.
　本発明に係るフレキシブルプリント配線板用圧延銅箔の一実施形態においては、前記第１基板と第２基板との基板間距離が１０ｍｍ以下であり、且つ、前記第１基板及び第２基板の少なくとも１つは、前記フレキシブルプリント配線板が設けられる領域を含む基板端部の長さが２００ｍｍ以上である。 In one embodiment of the rolled copper foil for a flexible printed wiring board according to the present invention, the distance between the first substrate and the second substrate is 10 mm or less, and at least the first substrate and the second substrate. One is that the length of the end portion of the substrate including the region where the flexible printed wiring board is provided is 200 mm or more.
　本発明に係るフレキシブルプリント配線板用圧延銅箔の別の実施形態においては、平面視において、前記フレキシブルプリント配線板のベースフィルムと前記銅箔との接触面の面積が、前記フレキシブルプリント配線板の表面積の５０％未満である。 In another embodiment of the rolled copper foil for a flexible printed wiring board according to the present invention, in plan view, the area of the contact surface between the base film of the flexible printed wiring board and the copper foil is that of the flexible printed wiring board. Less than 50% of the surface area.
　本発明に係るフレキシブルプリント配線板用圧延銅箔の更に別の一実施形態においては、前記フレキシブルプリント配線板の配線幅の最小値が２５μｍ以下である。 In yet another embodiment of the rolled copper foil for flexible printed wiring board according to the present invention, the minimum value of the wiring width of the flexible printed wiring board is 25 μm or less.
　本発明に係るフレキシブルプリント配線板用圧延銅箔の更に別の一実施形態においては、前記銅箔には、前記フレキシブルプリント配線板のベースフィルム側表面に、Ｃｒ及びＮｉが合計で５０～１０００μｇ／ｄｍ2付着しており、前記表面における表面粗さ（Ｒａ）がＲａ≦０．２μｍである。 In yet another embodiment of the rolled copper foil for a flexible printed wiring board according to the present invention, the copper foil has a total of 50 to 1000 μg / Cr on the base film side surface of the flexible printed wiring board. dm 2 is adhered, and the surface roughness (Ra) on the surface is Ra ≦ 0.2 μm.
　本発明に係るフレキシブルプリント配線板用圧延銅箔の更に別の一実施形態においては、前記銅箔には、前記フレキシブルプリント配線板のベースフィルム側表面に、必須成分としてのＣｒ及びＮｉ、さらにＳｎ、Ｃｏ、Ｖ、Ｔｉ、Ｚｎ、Ｍｎ及びＦｅからなる群から選択される１種又は２種以上が、合計で５０～１０００μｇ／ｄｍ2付着している。 In another embodiment of the rolled copper foil for flexible printed wiring boards according to the present invention, the copper foil includes Cr and Ni as essential components on the base film side surface of the flexible printed wiring board, and Sn. One or two or more selected from the group consisting of Co, V, Ti, Zn, Mn, and Fe adhere in a total of 50 to 1000 μg / dm 2 .
　本発明に係るフレキシブルプリント配線板用圧延銅箔の更に別の一実施形態においては、前記銅箔のＣｒ及びＮｉが付着した表面の反対側表面に、Ｐｄ、Ａｇ、Ａｕ、Ｃｒ、Ｎｉ、Ｓｎ及びＶからなる群から選択される１種又は２種以上が、合計で５０～１０００μｇ／ｄｍ2付着している。 In still another embodiment of the rolled copper foil for flexible printed wiring board according to the present invention, Pd, Ag, Au, Cr, Ni, Sn are formed on the surface of the copper foil opposite to the surface to which Cr and Ni are adhered. And one or more selected from the group consisting of V and V are attached in a total of 50 to 1000 μg / dm 2 .
　本発明に係るフレキシブルプリント配線板用圧延銅箔の更に別の一実施形態においては、前記付着元素にはＰｄが必須で含まれている。 In yet another embodiment of the rolled copper foil for a flexible printed wiring board according to the present invention, the adhering element essentially contains Pd.
　本発明に係るフレキシブルプリント配線板用圧延銅箔の更に別の一実施形態においては、前記銅箔が、タフピッチ銅又は無酸素銅で形成されている。 In yet another embodiment of the rolled copper foil for flexible printed wiring board according to the present invention, the copper foil is formed of tough pitch copper or oxygen-free copper.
　本発明に係るフレキシブルプリント配線板用圧延銅箔の更に別の一実施形態においては、前記銅箔が、タフピッチ銅又は無酸素銅にＡｇ、Ｓｎ、Ｃｒ、Ｚｒ、Ｆｅ、Ａｓ、Ｓｂ、Ｂｉ、Ｓｅ、Ｔｅ及びＰｂの少なくとも１種または２種以上を合計で２０００ｐｐｍ以下（０ｐｐｍを除く）添加した銅合金で形成されている。 In yet another embodiment of the flexible printed circuit board for the rolled copper foil according to the present invention, the copper foil, Ag the tough pitch copper or oxygen-free copper, Sn, Cr, Zr, Fe, As, Sb, Bi, It is formed of a copper alloy to which at least one or two or more of Se, Te, and Pb are added in a total of 2000 ppm or less (excluding 0 ppm).
　本発明は別の一側面において、本発明に係る銅箔を備えた銅張積層板である。 In another aspect, the present invention is a copper clad laminate provided with the copper foil according to the present invention.
　本発明は更に別の一側面において、本発明に係る銅張積層板を材料としたフレキシブルプリント配線板である。 In yet another aspect, the present invention is a flexible printed wiring board made of the copper clad laminate according to the present invention.
　本発明は更に別の一側面において、本発明に係るフレキシブルプリント配線板と、前記フレキシブルプリント配線板で電気的に接続された第１の基板及び第２の基板とを備えた電子機器である。 Further another aspect of the present invention is an electronic device including the flexible printed wiring board according to the present invention and a first substrate and a second substrate electrically connected by the flexible printed wiring board.
　本発明によれば、フレキシブルプリント配線板の配線として用いられたときに、長期の使用によっても配線にクラックが発生しない圧延銅箔、及び、それを用いた銅張積層板、フレキシブルプリント配線板及び電子機器を提供することができる。 According to the present invention, when used as a wiring of a flexible printed wiring board, a rolled copper foil that does not crack in wiring even after long-term use, and a copper-clad laminate, a flexible printed wiring board using the rolled copper foil, and An electronic device can be provided.
フレキシブルプリント配線板に対して行う温度変化の繰り返し試験の説明図である。It is explanatory drawing of the repeated test of the temperature change performed with respect to a flexible printed wiring board. 第１基板又は第２基板における、フレキシブルプリント配線板が設けられる領域（接続部）、及び、当該領域を含む基板端部を示す図である。It is a figure which shows the area | region (connection part) in which a flexible printed wiring board is provided in a 1st board | substrate or a 2nd board | substrate, and the board | substrate edge part containing the said area | region. 第１基板及び第２基板と、それらの間に形成されたフレキシブルプリント配線板との接続形態の種々のパターン（パターン１～４）を示す。Various patterns (patterns 1 to 4) of the connection form between the first substrate and the second substrate and the flexible printed wiring board formed between them are shown. 第１基板及び第２基板と、それらの間に形成されたフレキシブルプリント配線板との接続形態の種々のパターン（パターン５～７）を示す。Various patterns (patterns 5 to 7) of the connection form between the first substrate and the second substrate and the flexible printed wiring board formed therebetween are shown.
（フレキシブルプリント配線板用圧延銅箔の構成）
　フレキシブルプリント配線板用圧延銅箔の材料としては、タフピッチ銅や無酸素銅が使用可能である。
　さらには、タフピッチ銅及び無酸素銅をベースした銅合金箔も使用可能である。タフピッチ銅及び無酸素銅をベースした銅合金箔は、具体的には、Ａｇ、Ｓｎ、Ｃｒ、Ｚｒ、Ｆｅ、Ａｓ、Ｓｂ、Ｂｉ、Ｓｅ、Ｔｅ及びＰｂの少なくとも１種または２種以上を合計で２０００ｐｐｍ以下（０ｐｐｍを除く）、好ましくは５ｐｐｍ以上１５００ｐｐｍ以下、より好ましくは２０ｐｐｍ以上１０００ｐｐｍ以下添加したものである。ここで、「ｐｐｍ」とは質量ｐｐｍを意味する。
　なお、本明細書において用語「銅箔」を単独で用いたときには銅合金箔も含むものとし、「タフピッチ銅及び無酸素銅」を単独で用いたときにはタフピッチ銅及び無酸素銅をベースとした銅合金箔を含むものとする。 (Configuration of rolled copper foil for flexible printed wiring boards)
As a material of the rolled copper foil for flexible printed wiring boards, tough pitch copper or oxygen-free copper can be used.
Furthermore, copper alloy foils based on tough pitch copper and oxygen-free copper can also be used. Specifically, the copper alloy foil based on tough pitch copper and oxygen-free copper is a total of at least one or more of Ag, Sn, Cr, Zr, Fe, As, Sb, Bi, Se, Te and Pb. And 2000 ppm or less (excluding 0 ppm), preferably 5 ppm to 1500 ppm, more preferably 20 ppm to 1000 ppm. Here, “ppm” means mass ppm.
In addition, when the term “copper foil” is used alone in this specification, the copper alloy foil is also included. When “tough pitch copper and oxygen-free copper” is used alone, copper alloy based on tough pitch copper and oxygen-free copper is used. Includes foil.
　本発明に用いることのできる銅箔の厚さとしては、５～１８μｍが好ましい。銅箔の厚さが５μｍ未満であると銅箔のハンドリングが悪くなり、１８μｍ超であるとファインエッチング性が低下する。 The thickness of the copper foil that can be used in the present invention is preferably 5 to 18 μm. When the thickness of the copper foil is less than 5 μm, the handling of the copper foil is deteriorated, and when it is more than 18 μm, the fine etching property is deteriorated.
（フレキシブルプリント配線板の構成）
　本発明に係るフレキシブルプリント配線板は、絶縁基板と、この絶縁基板の表面に形成された配線パターンとを備えている。絶縁基板は、フレキシブルプリント配線板に適用可能な良好な屈曲性及び折れ曲げ性を有するものであれば特に制限を受けないが、例えば、ポリイミドフィルムや液晶ポリマーフィルム等を使用することができる。配線パターンは、上述のフレキシブルプリント配線板用圧延銅箔を用いて形成されている。配線パターンの形状は特に限定されず、どのようなものであってもよい。 (Configuration of flexible printed wiring board)
A flexible printed wiring board according to the present invention includes an insulating substrate and a wiring pattern formed on the surface of the insulating substrate. The insulating substrate is not particularly limited as long as it has good bendability and bendability applicable to a flexible printed wiring board. For example, a polyimide film or a liquid crystal polymer film can be used. The wiring pattern is formed using the above-mentioned rolled copper foil for flexible printed wiring boards. The shape of the wiring pattern is not particularly limited, and any shape may be used.
（フレキシブルプリント配線板の特性）
　本発明に係るフレキシブルプリント配線板は、上述のようなフレキシブルプリント配線板用圧延銅箔を用いて形成されているため、以下の特性を有する。すなわち、フレキシブルプリント配線板が電気的に接続する第１基板及び第２基板について、両基板が１．２倍以上の線熱膨張係数の差を有している場合、フレキシブルプリント配線板に対して－１０℃～＋９０℃の温度変化を１０００回繰り返しても配線にクラックが発生しない。さらに、両基板が１．５倍以上の線熱膨張係数の差を有している場合でも、フレキシブルプリント配線板に対して－１０℃～＋９０℃の温度変化を１０００回繰り返しても配線にクラックが発生しない。フレキシブルプリント配線板が電気的に接続している第１基板及び第２基板の線熱膨張係数の差が大きければ大きいほど、フレキシブルプリント配線板に加わる応力集中が大きくなる。通常、第１基板及び第２基板の線熱膨張係数の差が１．５倍以上であれば、温度変化によって両基板の膨張の差によって発生する応力集中に耐え切れず、フレキシブルプリント配線板の配線にクラックが生じる可能性が高い。また、第１基板及び第２基板の線膨張係数の差が１．２倍以上であってもフレキシブルプリント配線板の配線にクラックが生じる可能性がある。これに対し、本発明においては、このような状態においても配線へのクラックの発生が良好に抑制される。
　ここで、「フレキシブルプリント配線板に対して－１０℃～＋９０℃の温度変化を１０００回繰り返す」とは、図１に示すように、フレキシブルプリント配線板に対して高温槽及び低温槽にてそれぞれ９０℃及び－１０℃で３０分間保持し、これを１サイクルとして１０００サイクル繰り返すことをいう。なお、高温槽と低温槽との間の移し変えは１分間以内で行う。その他の条件はＪＩＳ　Ｃ００２５に従うことで行う。
　図２に、第１基板又は第２基板における、フレキシブルプリント配線板が設けられる領域（接続部）、及び、当該領域を含む基板端部を示す。上記線熱膨張係数は、この基板端部が延びる方向と平行な方向の膨張係数であり、室温での値を用いる。 (Characteristics of flexible printed wiring board)
Since the flexible printed wiring board which concerns on this invention is formed using the above rolled copper foil for flexible printed wiring boards, it has the following characteristics. That is, with respect to the first printed circuit board and the second printed circuit board to which the flexible printed wiring board is electrically connected, when both boards have a difference in linear thermal expansion coefficient of 1.2 times or more, the flexible printed wiring board Even if the temperature change from −10 ° C. to + 90 ° C. is repeated 1000 times, the wiring does not crack. Furthermore, even when the two substrates have a difference in linear thermal expansion coefficient of 1.5 times or more, the wiring is cracked even if the temperature change of -10 ° C to + 90 ° C is repeated 1000 times with respect to the flexible printed wiring board Does not occur. The greater the difference in coefficient of linear thermal expansion between the first substrate and the second substrate to which the flexible printed wiring board is electrically connected, the greater the concentration of stress applied to the flexible printed wiring board. Normally, if the difference in linear thermal expansion coefficient between the first substrate and the second substrate is 1.5 times or more, it cannot withstand the stress concentration caused by the difference in expansion between the two substrates due to temperature change, and the flexible printed wiring board There is a high possibility of cracks in the wiring. Moreover, even if the difference between the linear expansion coefficients of the first substrate and the second substrate is 1.2 times or more, there is a possibility that cracks may occur in the wiring of the flexible printed wiring board. On the other hand, in the present invention, the occurrence of cracks in the wiring is well suppressed even in such a state.
Here, “the temperature change from −10 ° C. to + 90 ° C. is repeated 1000 times with respect to the flexible printed wiring board” means that, as shown in FIG. Holding at 90 ° C. and −10 ° C. for 30 minutes means repeating this 1000 times as one cycle. In addition, the transfer between a high temperature tank and a low temperature tank is performed within 1 minute. Other conditions are performed according to JIS C0025.
FIG. 2 shows a region (connection portion) where the flexible printed wiring board is provided in the first substrate or the second substrate, and a substrate end including the region. The linear thermal expansion coefficient is an expansion coefficient in a direction parallel to the extending direction of the substrate end, and a value at room temperature is used.
　また、本発明に係るフレキシブルプリント配線板は、別の実施形態においては、線熱膨張係数が１．２倍以上差のある第１基板と第２基板とを電気的に接続するフレキシブルプリント配線板の配線として用いたときに、フレキシブルプリント配線板に対して－６５℃～＋１００℃の温度変化を１００回繰り返しても配線にクラックが発生しない。さらに、両基板が１．５倍以上の線熱膨張係数の差を有している場合でも、フレキシブルプリント配線板に対して－６５℃～＋１００℃の温度変化を１００回繰り返しても配線にクラックが発生しない。
　ここで、「フレキシブルプリント配線板に対して－６５℃～＋１００℃の温度変化を１００回繰り返す」とは、図１に示すように、フレキシブルプリント配線板に対して高温槽及び低温槽にてそれぞれ１００℃及び－６５℃で３０分間保持し、これを１サイクルとして１００サイクル繰り返すことをいう。なお、高温槽と低温槽との間の移し変えは１分間以内で行う。その他の条件はＪＩＳ　Ｃ００２５に従うことで行う。 In another embodiment, the flexible printed wiring board according to the present invention is a flexible printed wiring board that electrically connects a first board and a second board having a linear thermal expansion coefficient difference of 1.2 times or more. When used as a wiring, the crack does not occur in the wiring even if the temperature change of −65 ° C. to + 100 ° C. is repeated 100 times with respect to the flexible printed wiring board. Furthermore, even if the two substrates have a difference in linear thermal expansion coefficient of 1.5 times or more, the wiring is cracked even if the temperature change from -65 ° C to + 100 ° C is repeated 100 times with respect to the flexible printed wiring board Does not occur.
Here, “the temperature change from −65 ° C. to + 100 ° C. is repeated 100 times with respect to the flexible printed wiring board” means that, as shown in FIG. Holding at 100 ° C. and −65 ° C. for 30 minutes means repeating this 100 cycles as one cycle. In addition, the transfer between a high temperature tank and a low temperature tank is performed within 1 minute. Other conditions are performed according to JIS C0025.
　また、本発明に係るフレキシブルプリント配線板は、別の実施形態においては、線熱膨張係数が１．２倍以上差のある第１基板と第２基板とを電気的に接続するフレキシブルプリント配線板の配線として用いたときに、フレキシブルプリント配線板に対して－６５℃～＋１２５℃の温度変化を１００回繰り返しても配線にクラックが発生しない。さらに、両基板が１．５倍以上の線熱膨張係数の差を有している場合でも、フレキシブルプリント配線板に対して－６５℃～＋１２５℃の温度変化を１００回繰り返しても配線にクラックが発生しない。
　ここで、「フレキシブルプリント配線板に対して－６５℃～＋１２５℃の温度変化を１００回繰り返す」とは、図１に示すように、フレキシブルプリント配線板に対して高温槽及び低温槽にてそれぞれ１２５℃及び－６５℃で３０分間保持し、これを１サイクルとして１００サイクル繰り返すことをいう。なお、高温槽と低温槽との間の移し変えは１分間以内で行う。その他の条件はＪＩＳ　Ｃ００２５に従うことで行う。 In another embodiment, the flexible printed wiring board according to the present invention is a flexible printed wiring board that electrically connects a first board and a second board having a linear thermal expansion coefficient difference of 1.2 times or more. When used as a wiring, no cracks occur in the wiring even if the temperature change of −65 ° C. to + 125 ° C. is repeated 100 times with respect to the flexible printed wiring board. Furthermore, even when both boards have a difference in linear thermal expansion coefficient of 1.5 times or more, the wiring is cracked even if the temperature change of -65 ° C to + 125 ° C is repeated 100 times with respect to the flexible printed wiring board. Does not occur.
Here, “the temperature change from −65 ° C. to + 125 ° C. is repeated 100 times with respect to the flexible printed wiring board” means that, as shown in FIG. This is to hold at 125 ° C. and −65 ° C. for 30 minutes and repeat this for 100 cycles. In addition, the transfer between a high temperature tank and a low temperature tank is performed within 1 minute. Other conditions are performed according to JIS C0025.
　また、第１基板と第２基板との基板間距離が１０ｍｍ以下であり、第１基板及び第２基板の少なくとも１つは、本発明に係るフレキシブルプリント配線板が設けられる領域を含む基板端部の長さが２００ｍｍ以上であってもよい。図２に、第１基板又は第２基板における、フレキシブルプリント配線板が設けられる領域（接続部）、及び、当該領域を含む基板端部を示す。フレキシブルプリント配線板が設けられる領域を含む第１基板及び第２基板の基板端部の長さが長ければ長いほど、フレキシブルプリント配線板に加わる応力集中が大きくなる。通常、第１基板と第２基板との基板間距離が１０ｍｍ以下であるとき、フレキシブルプリント配線板が設けられる領域を含む第１基板又は第２基板の基板端部の長さが２００ｍｍ以上であれば、温度変化によって両基板の膨張の差によって発生する応力集中に耐え切れず、フレキシブルプリント配線板の配線にクラックが生じる可能性が高い。これに対し、本発明においては、このような状態においても配線へのクラックの発生が良好に抑制される。 Further, the distance between the substrates of the first substrate and the second substrate is 10 mm or less, and at least one of the first substrate and the second substrate includes a region where the flexible printed wiring board according to the present invention is provided. The length may be 200 mm or more. FIG. 2 shows a region (connection portion) where the flexible printed wiring board is provided in the first substrate or the second substrate, and a substrate end including the region. The longer the lengths of the substrate end portions of the first substrate and the second substrate including the region where the flexible printed wiring board is provided, the greater the concentration of stress applied to the flexible printed wiring board. In general, when the distance between the first substrate and the second substrate is 10 mm or less, the length of the substrate end portion of the first substrate or the second substrate including the region where the flexible printed wiring board is provided is 200 mm or more. For example, it is difficult to withstand the stress concentration caused by the difference in expansion between the two substrates due to temperature change, and there is a high possibility that the wiring of the flexible printed wiring board will crack. On the other hand, in the present invention, the occurrence of cracks in the wiring is well suppressed even in such a state.
　また、平面視において、フレキシブルプリント配線板のベースフィルムと銅箔との接触面の面積がフレキシブルプリント配線板の表面積の５０％未満であってもよい。圧延銅箔の配線パターンにはフレキシブルプリント配線板を固定して耐応力特性を向上させる働きがある。そのため、逆にフレキシブルプリント配線板におけるフレキシブルプリント配線板用圧延銅箔の表面積が小さくなれば、それだけフレキシブルプリント配線板の耐応力特性が低下する。通常、フレキシブルプリント配線板用圧延銅箔の表面積がフレキシブルプリント配線板の表面積の５０％未満であれば、温度変化によって両基板の膨張の差によって発生する応力集中に耐え切れず、フレキシブルプリント配線板の配線にクラックが生じる可能性が高い。これに対し、本発明においては、このような状態においても配線へのクラックの発生が良好に抑制される。 Further, in plan view, the area of the contact surface between the base film of the flexible printed wiring board and the copper foil may be less than 50% of the surface area of the flexible printed wiring board. The wiring pattern of the rolled copper foil has the function of fixing the flexible printed wiring board and improving the stress resistance characteristics. Therefore, conversely, if the surface area of the rolled copper foil for flexible printed wiring board in the flexible printed wiring board is reduced, the stress resistance characteristic of the flexible printed wiring board is lowered accordingly. Usually, if the surface area of the rolled copper foil for a flexible printed wiring board is less than 50% of the surface area of the flexible printed wiring board, the flexible printed wiring board cannot withstand the stress concentration caused by the difference in expansion between the two substrates due to temperature changes. There is a high possibility that cracks will occur in the wiring. On the other hand, in the present invention, the occurrence of cracks in the wiring is well suppressed even in such a state.
　また、フレキシブルプリント配線板の配線パターンを構成する各配線幅の最小値が２５μｍ以下であってもよい。フレキシブルプリント配線板の配線は、その幅が小さければ小さいほど、フレキシブルプリント配線板に加わる応力集中によってクラックを発生させやすい。通常、配線幅の最小値が２５μｍ以下であれば、温度変化によって両基板の膨張の差によって発生する応力集中に耐え切れず、クラックが生じる可能性が高い。これに対し、本発明においては、このような状態においても配線へのクラックの発生が良好に抑制される。 Further, the minimum value of each wiring width constituting the wiring pattern of the flexible printed wiring board may be 25 μm or less. The smaller the width of the flexible printed wiring board, the easier it is to generate cracks due to stress concentration applied to the flexible printed wiring board. Usually, if the minimum value of the wiring width is 25 μm or less, the stress concentration generated by the difference in expansion between the two substrates due to temperature change cannot be withstood, and there is a high possibility that a crack will occur. On the other hand, in the present invention, the occurrence of cracks in the wiring is well suppressed even in such a state.
　本発明に係る圧延銅箔には、フレキシブルプリント配線板のベースフィルム側表面に、Ｃｒ及びＮｉが合計で５０～１０００μｇ／ｄｍ2付着していてもよい。このような構成によれば、銅箔の密着性及び耐熱性が向上するという効果を有する。Ｃｒ及びＮｉの付着量が合計で５０μｇ／ｄｍ2未満であると、銅箔の密着性及び耐熱性が不良となる。また、Ｃｒ及びＮｉの付着量が合計で１０００μｇ／ｄｍ2超であると、エッチング性が不良となる。
　また、当該表面における表面粗さ（Ｒａ）は、Ｒａ≦０．２μｍであってもよい。このような構成によれば、銅箔のファインエッチング性が向上するという効果を有する。 In the rolled copper foil according to the present invention, a total of 50 to 1000 μg / dm 2 of Cr and Ni may be adhered to the base film side surface of the flexible printed wiring board. According to such a structure, it has the effect that the adhesiveness and heat resistance of copper foil improve. When the adhesion amount of Cr and Ni is less than 50 μg / dm 2 in total, the adhesion and heat resistance of the copper foil are poor. Further, if the total adhesion amount of Cr and Ni is more than 1000 μg / dm 2 , the etching property becomes poor.
Further, the surface roughness (Ra) on the surface may be Ra ≦ 0.2 μm. According to such a structure, it has the effect that the fine etching property of copper foil improves.
　本発明に係る圧延銅箔には、フレキシブルプリント配線板のベースフィルム側表面に、必須成分としてのＣｒ及びＮｉ、さらにＳｎ、Ｃｏ、Ｖ、Ｔｉ、Ｚｎ、Ｍｎ及びＦｅからなる群から選択される１種又は２種以上が、合計で５０～１０００μｇ／ｄｍ2付着していてもよい。このような構成によれば、密着性、耐熱性またはエッチング性が向上するという効果を有する。当該付着量が合計で５０μｇ／ｄｍ2未満であると、密着性、耐熱性またはエッチング性が不良となる。また、当該付着量が合計で１０００μｇ／ｄｍ2超であると、エッチング性が不良となる。 The rolled copper foil according to the present invention is selected from the group consisting of Cr and Ni as essential components, Sn, Co, V, Ti, Zn, Mn and Fe on the base film side surface of the flexible printed wiring board. One or two or more of them may be attached in a total of 50 to 1000 μg / dm 2 . According to such a configuration, there is an effect that adhesion, heat resistance or etching is improved. When the amount of adhesion is less than 50 μg / dm 2 in total, the adhesion, heat resistance or etching becomes poor. Further, if the total amount of adhesion is more than 1000 μg / dm 2 , the etching property becomes poor.
　本発明に係る圧延銅箔のＣｒ及びＮｉが付着した表面の反対側表面に、Ｐｄ、Ａｇ、Ａｕ、Ｃｒ、Ｎｉ、Ｓｎ及びＶからなる群から選択される１種又は２種以上が、合計で５０～１０００μｇ／ｄｍ2付着していてもよい。このような構成によれば、エッチング性が向上し、ファインピッチの回路を形成することができるという効果を有する。さらに、耐熱性が良好となる。当該付着量が合計で５０μｇ／ｄｍ2未満であると、エッチング性及び耐熱性が不良となる。また、当該付着量が合計で１０００μｇ／ｄｍ2超であると、エッチング性が不良となる。また、上記効果のためには、付着元素にはＰｄが必須で含まれているのがより好ましい。 One type or two or more types selected from the group consisting of Pd, Ag, Au, Cr, Ni, Sn and V are added to the surface opposite to the surface to which Cr and Ni of the rolled copper foil according to the present invention are attached. 50 to 1000 μg / dm 2 may be adhered. According to such a configuration, the etching property is improved, and there is an effect that a fine pitch circuit can be formed. Furthermore, heat resistance becomes favorable. When the adhesion amount is less than 50 μg / dm 2 in total, the etching property and heat resistance are poor. Further, if the total amount of adhesion is more than 1000 μg / dm 2 , the etching property becomes poor. For the above effect, it is more preferable that Pd is contained as an essential element in the adhering element.
（フレキシブルプリント配線板の製法）
　フレキシブルプリント配線板は、上記圧延銅箔を用い、常法に従って製造することができる。以下に、フレキシブルプリント配線板の製造例を示す。
　まず、圧延銅箔と、良好な屈曲性及び折れ曲げ性を有するポリイミドフィルム、液晶ポリマーフィルム等の絶縁基板とを貼り合わせて銅張積層板を製造する。 (Production method of flexible printed wiring board)
A flexible printed wiring board can be manufactured according to a conventional method using the rolled copper foil. Below, the manufacture example of a flexible printed wiring board is shown.
First, a copper clad laminate is manufactured by laminating a rolled copper foil and an insulating substrate such as a polyimide film or a liquid crystal polymer film having good flexibility and foldability.
　貼り合わせの方法は、ポリイミドフィルムの場合、熱硬化性ポリイミドフィルムに熱可塑性のポリイミド接着剤を塗工、乾燥した後、銅箔と積層させ、熱圧着させる。圧着方法としては真空熱プレスする方法や熱ロールによってラミネートする方法がある。またポリイミドフィルムの場合、銅箔にポリイミドの前駆体を塗工、乾燥、硬化させることで銅張積層板を作製する。 For the bonding method, in the case of a polyimide film, a thermoplastic polyimide adhesive is applied to the thermosetting polyimide film and dried, and then laminated with a copper foil and thermocompression bonded. As a pressure bonding method, there are a method of vacuum hot pressing and a method of laminating with a heat roll. Moreover, in the case of a polyimide film, a copper-clad laminate is produced by coating, drying and curing a polyimide precursor on a copper foil.
　銅張積層板からフレキシブルプリント配線板を作製する工程は当業者に周知の方法を用いればよい。例えば、エッチングレジストを銅張積層板の銅箔面に配線パターンとしての必要部分だけに塗工し、エッチング液を銅箔面に噴射することで不要銅箔を除去して回路パターンを形成する。次いでエッチングレジストを剥離・除去して配線パターンを露出することで、フレキシブルプリント配線板を作製する。 For the process of producing a flexible printed wiring board from a copper clad laminate, a method well known to those skilled in the art may be used. For example, an etching resist is applied only to a necessary portion as a wiring pattern on a copper foil surface of a copper clad laminate, and unnecessary copper foil is removed by spraying an etching solution onto the copper foil surface to form a circuit pattern. Next, a flexible printed wiring board is produced by peeling and removing the etching resist to expose the wiring pattern.
　このフレキシブルプリント配線板を２つの電子基板間に設けて、それらを電気的に接続させることで、種々の電子機器を作製することができる。電子機器としては、特に限定されず、例えば、液晶ディスプレイ、カーナビゲーション、携帯電話、ゲーム機、ＣＤプレイヤー、デジタルカメラ、テレビ、ＤＶＤプレイヤー、電子手帳、電子辞書、電卓、ビデオカメラ、プリンター等が挙げられる。 Various electronic devices can be manufactured by providing this flexible printed wiring board between two electronic boards and electrically connecting them. The electronic devices, is not particularly limited, for example, include a liquid crystal display, a car navigation, mobile phone, game machine, CD player, digital camera, TV, DVD player, electronic organizers, electronic dictionaries, calculators, video cameras, printers, etc. It is done.
　以下、本発明の実施例を示すが、これらは本発明をより良く理解するために提供するものであり、本発明が限定されることを意図するものではない。 Examples of the present invention will be described below, but these are provided for better understanding of the present invention and are not intended to limit the present invention.
（実施例）
　実施例１～５６、５７、５８、６１、６５、６６についてはタフピッチ銅インゴット、無酸素銅をベースにＡｇ、Ｓｎ、Ｃｒ、Ｚｒ、Ｆｅ、Ａｓ、Ｓｂ、Ｂｉ、Ｓｅ、Ｔｅ及びＰｂの少なくとも１種または２種以上を添加して作製したインゴットを熱間圧延で厚さ１０ｍｍの板に加工し、表面切削で酸化物を取り除いた後、冷間圧延、焼鈍と酸洗を繰り返して表１～３に記載の厚さまで加工して銅箔を作製し、この銅箔表面に表面処理をスパッタで施した。表面処理としては、フレキシブルプリント配線板のベースフィルムと接着させる表面（１）に、Ｃｒ、Ｎｉ、Ｓｎ、Ｃｏ、Ｖ、Ｔｉ、Ｚｎ、Ｍｎ、Ｆｅをスパッタにより付着させた。また、上記表面と逆側の表面（２）側に、Ｐｄ、Ａｇ、Ａｕ、Ｃｒ、Ｎｉ、Ｓｎ、Ｖをスパッタにより付着させた。
　実施例６２～６４については無酸素銅インゴットを用いた点、実施例５９、６０、６７、６８についてはタフピッチ銅をベースにＡｇ、Ｓｎ、Ｃｒ、Ｚｒ、Ｆｅ、Ａｓ、Ｓｂ、Ｂｉ、Ｓｅ、Ｔｅ及びＰｂの少なくとも１種または２種以上を添加して作製したインゴットを用いた点以外は上述と同じ方法により作製した。
　表面処理後、実施例１～３２、６３、６４、６６、６８はカプトンＥＮ（登録商標）に熱可塑性ＰＩ接着剤を１μｍ塗工、乾燥して形成した３８．５μｍ厚の樹脂層を銅箔に積層させて真空熱プレスによって銅張積層体を作製した。実施例３３～６２、６５、６７は銅箔にポリイミドワニス（宇部興産（株）製ＵワニスＳ）を塗工、乾燥、硬化させ３７．５μｍの樹脂層を形成させて銅張積層体を作製した。
　続いて、表１～３に記載の配線幅且つ面積率となるように、銅箔の配線パターンをエッチングにより形成した。ここで、各配線はその幅が互いに均等になるように形成した。以上の手順により、フレキシブルプリント配線板を作製した。このとき、銅箔と樹脂層との密着強度をいずれも０．７ｋＮ／ｍ以上あることを確かめ、試験中銅箔が剥離しないように制御した。
　続いて、表１～３、図３～４に示すような、それぞれＦＲ４等のリジッド基板及び/又はガラス基板を用いて形成された第１基板及び第２基板を準備し、所定の基板間距離を空けてフレキシブルプリント配線板を異方性導電接着フィルム（ＡＣＦ）により圧着した。ここで、図３～４は、それぞれ第１基板及び第２基板と、それらの間に形成されたフレキシブルプリント配線板との接続形態の種々のパターン（パターン１～７）を示す。
　ここで、パターン１～３、６、７は、平行で、且つ、Ｌ（ライン）/Ｓ（スペース）が一定の回路に形成されている。また、両サイドエッチ０．５ｍｍは回路が形成されていない。パターン２、３の配線板の長さは３５ｍｍである。
　パターン４、５は、回路が放射状に形成されている。パターン４、５は回路幅が変えられていないため、回路が広がっていく方向ではスペースが広くなるように、Ｌ/Ｓは場所によって異なる。第１基板及び第２基板の線熱膨張方向と平行な方向では、Ｌ/Ｓは等間隔の回路となっている。パターン４、５も両サイドエッジ０．５ｍｍは回路を形成していない。第１の基板、第２の基板は、各図に記載の線熱膨張係数の方向（矢印の向き）に膨張する。
　続いて、上述のようにして作製した、第１基板、第２基板及びそれらを電気的に接続するフレキシブルプリント配線板で構成された試料に対し、－１０℃～＋９０℃、又は、－６５～＋１００℃、又は、－６５～＋１２５℃の温度変化を繰り返し与え、フレキシブルプリント配線板の配線にクラックが生じたときの繰り返し回数を測定した。 (Example)
Examples 1 to 56, 57, 58, 61, 65, 66 are based on tough pitch copper ingots and oxygen-free copper, and are based on at least Ag, Sn, Cr, Zr, Fe, As, Sb, Bi, Se, Te, and Pb. An ingot produced by adding one or more kinds is processed into a plate having a thickness of 10 mm by hot rolling, the oxide is removed by surface cutting, and then cold rolling, annealing and pickling are repeated. A copper foil was produced by processing to the thickness described in (3) to (3), and surface treatment was applied to the surface of the copper foil by sputtering. As the surface treatment, Cr, Ni, Sn, Co, V, Ti, Zn, Mn, and Fe were adhered to the surface (1) to be bonded to the base film of the flexible printed wiring board by sputtering. Further, Pd, Ag, Au, Cr, Ni, Sn, and V were adhered to the surface (2) side opposite to the above surface by sputtering.
For Examples 62 to 64, an oxygen-free copper ingot was used. For Examples 59, 60, 67, and 68, based on tough pitch copper, Ag, Sn, Cr, Zr, Fe, As, Sb, Bi, Se, It was produced by the same method as described above except that an ingot produced by adding at least one of Te and Pb was used.
After surface treatment, Examples 1 to 32, 63, 64, 66, and 68 were obtained by applying a 18.5 μm thick thermoplastic PI adhesive to Kapton EN (registered trademark) and drying a 38.5 μm thick resin layer on a copper foil. A copper clad laminate was produced by vacuum hot pressing. Examples 33 to 62, 65, and 67 were prepared by applying polyimide varnish (U varnish S manufactured by Ube Industries Co., Ltd.) to copper foil, drying, and curing to form a 37.5 μm resin layer to produce a copper clad laminate. did.
Subsequently, a copper foil wiring pattern was formed by etching so that the wiring width and area ratio shown in Tables 1 to 3 were obtained. Here, each wiring was formed so that the width | variety might become equal mutually. The flexible printed wiring board was produced by the above procedure. At this time, it was confirmed that the adhesion strength between the copper foil and the resin layer was 0.7 kN / m or more, and the copper foil was controlled not to peel during the test.
Subsequently, as shown in Tables 1 to 3 and FIGS. 3 to 4, a first substrate and a second substrate formed using a rigid substrate such as FR4 and / or a glass substrate are prepared, and a predetermined inter-substrate distance is prepared. The flexible printed wiring board was pressure-bonded with an anisotropic conductive adhesive film (ACF). Here, FIGS. 3 to 4 show various patterns (patterns 1 to 7) of the connection form between the first substrate and the second substrate and the flexible printed wiring board formed therebetween, respectively.
Here, the patterns 1 to 3, 6, and 7 are formed in a circuit that is parallel and has a constant L (line) / S (space). Moreover, the circuit is not formed in both side etch 0.5mm. The length of the wiring boards of patterns 2 and 3 is 35 mm.
In the patterns 4 and 5, the circuits are formed in a radial pattern. Since the circuit widths of the patterns 4 and 5 are not changed, the L / S differs depending on the location so that the space becomes wider in the direction in which the circuit expands. In the direction parallel to the linear thermal expansion direction of the first substrate and the second substrate, L / S is a circuit with an equal interval. In the patterns 4 and 5, neither side edge of 0.5 mm forms a circuit. The first substrate and the second substrate expand in the direction of the linear thermal expansion coefficient (the direction of the arrow) shown in each drawing.
Subsequently, for the sample made of the first substrate, the second substrate, and the flexible printed wiring board that electrically connects them, manufactured as described above, −10 ° C. to + 90 ° C., or −65 to A temperature change of + 100 ° C. or −65 to + 125 ° C. was repeatedly applied, and the number of repetitions when a crack occurred in the wiring of the flexible printed wiring board was measured.
（比較例）
　比較例１～１６、１８として、東レ・デュポン株式会社製カプトンＥＮ（登録商標）を樹脂層として、密着性向上と後の工程でＣｕを電着させるための金属層Ｃｒ、Ｎｉ、Ｃｕをスパッタした後に、電着によって銅層を形成し、銅張積層体を作製した。樹脂層の厚さは３７．５μｍ厚とした。
　また、比較例１７として、三井金属鉱業社製電解銅箔ＮＡ-ＶＬＰにカプトンＥＮに熱可塑性ＰＩ接着剤を１μｍ塗工、乾燥して形成した３８．５μｍ厚の樹脂層を銅箔に積層させて真空熱プレスによって銅張積層体を作製した。
　続いて、表７に記載の配線幅且つ面積率となるように、銅箔の配線パターンをエッチングにより形成した。ここで、各配線はその幅が互いに均等になるように形成した。以上の手順により、フレキシブルプリント配線板を作製した。このとき、銅箔と樹脂層との密着強度をいずれも０．７ｋＮ／ｍ以上あることを確かめ、試験中銅箔が剥離しないように制御した。
　続いて、表７、図３～４に示すような、ＦＲ４等のリジッド基板及び/又はガラス基板を用いて形成された第１基板及び第２基板を準備し、基板間距離を６ｍｍとしてフレキシブルプリント配線板を異方性導電接着フィルム（ＡＣＦ）により圧着した。
　続いて、上述のようにして作製した、第１基板、第２基板及びそれらを電気的に接続するフレキシブルプリント配線板で構成された試料に対し、－１０℃～＋９０℃、又は、－６５～＋１００℃、又は、－６５～＋１２５℃の温度変化を繰り返し与え、フレキシブルプリント配線板の配線にクラックが生じたときの繰り返し回数を測定した。
　ここで、クラックの発生は以下のように判定した。すなわち、フレキシブルプリント配線板の配線に一定電流（０．０１～０．１ｍＡ）を流し、当該電流を流すために必要な電圧値を測定し、測定した電圧値からフレキシブルプリント配線板の配線の抵抗値を算出した。算出した抵抗値が初期値の５００％以上となったときに、クラックが生じたと判定した。
　また、ベースフィルム側の銅箔の表面（１）のＪＩＳ－Ｂ０６０１に準拠した算術平均粗さＲａ（μｍ）を測定した。算術平均粗さＲａ（μｍ）の測定には接触粗さ計（小坂研究所製、商品名「ＳＥ－３４００」）を使用した。
　各試験条件及び測定結果を表１～７に示す。 (Comparative example)
As Comparative Examples 1 to 16 and 18, Kapton EN (registered trademark) manufactured by Toray DuPont Co., Ltd. is used as a resin layer, and metal layers Cr, Ni, and Cu are sputtered to improve adhesion and electrodeposit Cu in a later step. After that, a copper layer was formed by electrodeposition to produce a copper clad laminate. The thickness of the resin layer was 37.5 μm.
Further, as Comparative Example 17, a 38.5 μm thick resin layer formed by applying 1 μm of thermoplastic PI adhesive to Kapton EN and drying on electrolytic copper foil NA-VLP manufactured by Mitsui Mining & Mining Co., Ltd. was laminated on the copper foil. Then, a copper clad laminate was produced by vacuum hot pressing.
Subsequently, a copper foil wiring pattern was formed by etching so that the wiring width and area ratio shown in Table 7 were obtained. Here, each wiring was formed so that the width | variety might become equal mutually. The flexible printed wiring board was produced by the above procedure. At this time, it was confirmed that the adhesion strength between the copper foil and the resin layer was 0.7 kN / m or more, and the copper foil was controlled not to peel during the test.
Subsequently, as shown in Table 7 and FIGS. 3 to 4, a first substrate and a second substrate formed using a rigid substrate such as FR4 and / or a glass substrate are prepared, and the distance between the substrates is set to 6 mm. The wiring board was pressure-bonded with an anisotropic conductive adhesive film (ACF).
Subsequently, for the sample made of the first substrate, the second substrate, and the flexible printed wiring board that electrically connects them, manufactured as described above, −10 ° C. to + 90 ° C., or −65 to A temperature change of + 100 ° C. or −65 to + 125 ° C. was repeatedly given, and the number of repetitions when a crack occurred in the wiring of the flexible printed wiring board was measured.
Here, the occurrence of cracks was determined as follows. That is, a constant current (0.01 to 0.1 mA) is passed through the wiring of the flexible printed wiring board, a voltage value necessary to pass the current is measured, and the wiring resistance of the flexible printed wiring board is calculated from the measured voltage value. The value was calculated. When the calculated resistance value was 500% or more of the initial value, it was determined that a crack occurred.
Further, the arithmetic average roughness Ra (μm) based on JIS-B0601 of the surface (1) of the copper foil on the base film side was measured. A contact roughness meter (manufactured by Kosaka Laboratory, trade name “SE-3400”) was used to measure the arithmetic average roughness Ra (μm).
Tables 1 to 7 show the test conditions and measurement results.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
　実施例の配線はいずれもクラックが発生しなかった。また、平滑な銅箔表面であっても、温度変化の繰り返し中に良好な密着性が保たれ、ベースフィルムから剥がれることが無かった。また、ベースフィルムと反対側の表面にＰｄを付着させた銅箔は、圧延銅箔であってもファインパターンの回路を形成することが可能であることが確認された。また、実施例１０、２２、２９、３２、５７、６０、６２、６４～６８で－６５～＋１２５℃の温度変化の繰り返しを行ったが１００回のサイクル後も配線にクラックは発生しなかった。
　比較例では、線熱膨張係数の差が大きいほど、回路幅が狭いほど、基板が長いほど、配線の面積率が低いほど、配線にクラックが発生する温度変化のサイクル数が少なくなっていることが確認された。なお、比較例１３、１５、１６、１８でも－６５～＋１２５℃の温度変化の繰り返しを行った。その結果、それぞれ比較例１３では４９回、比較例１５では３２回、比較例１６では４３回、比較例１８では３３回のサイクルで配線にクラックが生じた。 None of the wirings of the examples had cracks. Moreover, even if it was the smooth copper foil surface, favorable adhesiveness was maintained during the repetition of a temperature change, and it did not peel from a base film. Moreover, it was confirmed that even if the copper foil having Pd attached to the surface opposite to the base film is a rolled copper foil, a fine pattern circuit can be formed. Further, in Examples 10, 22, 29, 32, 57, 60, 62, and 64 to 68, a temperature change of −65 to + 125 ° C. was repeated, but no crack was generated in the wiring even after 100 cycles. .
In the comparative example, the larger the difference in coefficient of linear thermal expansion, the narrower the circuit width, the longer the substrate, the lower the area ratio of the wiring, the fewer the number of cycles of temperature change that causes cracks in the wiring. Was confirmed. In Comparative Examples 13, 15, 16, and 18, the temperature change of −65 to + 125 ° C. was repeated. As a result, cracks occurred in the wiring in 49 cycles in Comparative Example 13, 32 in Comparative Example 15, 43 in Comparative Example 16, and 33 in Comparative Example 18.

Claims (18)

  1. 　線熱膨張係数が１．２倍以上差のある第１基板と第２基板とを電気的に接続するフレキシブルプリント配線板の配線として用いたときに、前記フレキシブルプリント配線板を－１０℃～＋９０℃の温度変化を１０００回繰り返しても前記配線にクラックが発生しないフレキシブルプリント配線板用圧延銅箔。 When the flexible printed wiring board is used as a wiring of a flexible printed wiring board that electrically connects the first board and the second board having a difference of linear thermal expansion coefficient of 1.2 times or more, the flexible printed wiring board is −10 ° C. to + 90 ° C. A rolled copper foil for a flexible printed wiring board in which cracks are not generated in the wiring even when a temperature change of 1000C is repeated 1000 times.
  2. 　線熱膨張係数が１．５倍以上差のある第１基板と第２基板とを電気的に接続するフレキシブルプリント配線板の配線として用いたときに、前記フレキシブルプリント配線板を－１０℃～＋９０℃の温度変化を１０００回繰り返しても前記配線にクラックが発生しないフレキシブルプリント配線板用圧延銅箔。 When the flexible printed wiring board is used as a wiring of a flexible printed wiring board that electrically connects the first board and the second board having a linear thermal expansion coefficient difference of 1.5 times or more, the flexible printed wiring board is −10 ° C. to + 90 ° C. A rolled copper foil for a flexible printed wiring board in which cracks are not generated in the wiring even when a temperature change of 1000C is repeated 1000 times.
  3. 　線熱膨張係数が１．２倍以上差のある第１基板と第２基板とを電気的に接続するフレキシブルプリント配線板の配線として用いたときに、前記フレキシブルプリント配線板を－６５℃～＋１００℃の温度変化を１００回繰り返しても前記配線にクラックが発生しないフレキシブルプリント配線板用圧延銅箔。 When the flexible printed wiring board is used as a wiring of a flexible printed wiring board that electrically connects the first substrate and the second substrate having a difference of linear thermal expansion coefficient of 1.2 times or more, the flexible printed wiring board is −65 ° C. to + 100 ° C. A rolled copper foil for a flexible printed wiring board, in which cracks do not occur in the wiring even when a temperature change of 100 ° C. is repeated 100 times.
  4. 　線熱膨張係数が１．５倍以上差のある第１基板と第２基板とを電気的に接続するフレキシブルプリント配線板の配線として用いたときに、前記フレキシブルプリント配線板を－６５℃～＋１００℃の温度変化を１００回繰り返しても前記配線にクラックが発生しないフレキシブルプリント配線板用圧延銅箔。 When the flexible printed wiring board is used as a wiring of a flexible printed wiring board that electrically connects the first board and the second board having a linear thermal expansion coefficient difference of 1.5 times or more, the flexible printed wiring board is −65 ° C. to + 100 ° C. A rolled copper foil for a flexible printed wiring board, in which cracks do not occur in the wiring even when a temperature change of 100 ° C. is repeated 100 times.
  5. 　線熱膨張係数が１．２倍以上差のある第１基板と第２基板とを電気的に接続するフレキシブルプリント配線板の配線として用いたときに、前記フレキシブルプリント配線板を－６５℃～＋１２５℃の温度変化を１００回繰り返しても前記配線にクラックが発生しないフレキシブルプリント配線板用圧延銅箔。 When the flexible printed wiring board is used as a wiring of a flexible printed wiring board that electrically connects the first board and the second board having a difference in linear thermal expansion coefficient of 1.2 times or more, the flexible printed wiring board is −65 ° C. to + 125 ° C. A rolled copper foil for a flexible printed wiring board, in which cracks do not occur in the wiring even when a temperature change of 100 ° C. is repeated 100 times.
  6. 　線熱膨張係数が１．５倍以上差のある第１基板と第２基板とを電気的に接続するフレキシブルプリント配線板の配線として用いたときに、前記フレキシブルプリント配線板を－６５℃～＋１２５℃の温度変化を１００回繰り返しても前記配線にクラックが発生しないフレキシブルプリント配線板用圧延銅箔。 When the flexible printed wiring board is used as a wiring of a flexible printed wiring board that electrically connects the first board and the second board having a linear thermal expansion coefficient difference of 1.5 times or more, the flexible printed wiring board is −65 ° C. to + 125 ° C. A rolled copper foil for a flexible printed wiring board in which cracks do not occur in the wiring even when the temperature change of ° C. is repeated 100 times.
  7. 　前記第１基板と第２基板との基板間距離が１０ｍｍ以下であり、且つ、前記第１基板及び第２基板の少なくとも１つは、前記フレキシブルプリント配線板が設けられる領域を含む基板端部の長さが２００ｍｍ以上である請求項１～６のいずれかに記載のフレキシブルプリント配線板用圧延銅箔。 The distance between the first substrate and the second substrate is 10 mm or less, and at least one of the first substrate and the second substrate is a substrate end portion including a region where the flexible printed wiring board is provided. The rolled copper foil for flexible printed wiring boards according to any one of claims 1 to 6, which has a length of 200 mm or more.
  8. 　平面視において、前記フレキシブルプリント配線板のベースフィルムと前記銅箔との接触面の面積が、前記フレキシブルプリント配線板の表面積の５０％未満である請求項１～７のいずれかに記載のフレキシブルプリント配線板用圧延銅箔。 The flexible print according to any one of claims 1 to 7, wherein an area of a contact surface between the base film of the flexible printed wiring board and the copper foil is less than 50% of a surface area of the flexible printed wiring board in a plan view. Rolled copper foil for wiring boards.
  9. 　前記フレキシブルプリント配線板の配線幅の最小値が２５μｍ以下である請求項１～８のいずれかに記載のフレキシブルプリント配線板用圧延銅箔。 The rolled copper foil for a flexible printed wiring board according to any one of claims 1 to 8, wherein the minimum value of the wiring width of the flexible printed wiring board is 25 µm or less.
  10. 　前記銅箔には、前記フレキシブルプリント配線板のベースフィルム側表面に、Ｃｒ及びＮｉが合計で５０～１０００μｇ／ｄｍ2付着しており、前記表面における表面粗さ（Ｒａ）がＲａ≦０．２μｍである請求項１～９のいずれかに記載のフレキシブルプリント配線板用圧延銅箔。 The copper foil has a total of 50 to 1000 μg / dm 2 of Cr and Ni adhering to the base film side surface of the flexible printed wiring board, and the surface roughness (Ra) on the surface is Ra ≦ 0.2 μm. The rolled copper foil for flexible printed wiring boards according to any one of claims 1 to 9.
  11. 　前記銅箔には、前記フレキシブルプリント配線板のベースフィルム側表面に、必須成分としてのＣｒ及びＮｉ、さらにＳｎ、Ｃｏ、Ｖ、Ｔｉ、Ｚｎ、Ｍｎ及びＦｅからなる群から選択される１種又は２種以上が、合計で５０～１０００μｇ／ｄｍ2付着している請求項１０に記載のフレキシブルプリント配線板用圧延銅箔。 In the copper foil, on the base film side surface of the flexible printed wiring board, one or more selected from the group consisting of Cr and Ni as essential components, and further Sn, Co, V, Ti, Zn, Mn and Fe The rolled copper foil for flexible printed wiring boards according to claim 10, wherein two or more kinds are adhered in total in a range of 50 to 1000 μg / dm 2 .
  12. 　前記銅箔のＣｒ及びＮｉが付着した表面の反対側表面に、Ｐｄ、Ａｇ、Ａｕ、Ｃｒ、Ｎｉ、Ｓｎ及びＶからなる群から選択される１種又は２種以上が、合計で５０～１０００μｇ／ｄｍ2付着している請求項１１に記載のフレキシブルプリント配線板用圧延銅箔。 One or more selected from the group consisting of Pd, Ag, Au, Cr, Ni, Sn, and V on the opposite surface of the surface of the copper foil to which Cr and Ni are adhered, totaling 50 to 1000 μg The rolled copper foil for flexible printed wiring boards according to claim 11, wherein / dm 2 is adhered.
  13. 　前記付着元素にはＰｄが必須で含まれている請求項１２に記載のフレキシブルプリント配線板用圧延銅箔。 The rolled copper foil for a flexible printed wiring board according to claim 12, wherein Pd is essential in the adhering element.
  14. 　前記銅箔が、タフピッチ銅又は無酸素銅で形成されている請求項１～１３のいずれかに記載のフレキシブルプリント配線板用圧延銅箔。 The rolled copper foil for flexible printed wiring boards according to any one of claims 1 to 13, wherein the copper foil is formed of tough pitch copper or oxygen-free copper.
  15. 　前記銅箔が、タフピッチ銅又は無酸素銅にＡｇ、Ｓｎ、Ｃｒ、Ｚｒ、Ｆｅ、Ａｓ、Ｓｂ、Ｂｉ、Ｓｅ、Ｔｅ及びＰｂの少なくとも１種または２種以上を合計で２０００ｐｐｍ以下（０ｐｐｍを除く）添加した銅合金で形成されている請求項１～１３のいずれかに記載のフレキシブルプリント配線板用圧延銅箔。 The copper foil is tough pitch copper or oxygen-free copper, and includes Ag, Sn, Cr, Zr, Fe, As, Sb, Bi, Se, Te, and Pb in a total of 2000 ppm or less (excluding 0 ppm) The rolled copper foil for flexible printed wiring boards according to any one of claims 1 to 13, which is formed of an added copper alloy.
  16. 　請求項１～１５のいずれかに記載の銅箔を備えた銅張積層板。 A copper-clad laminate comprising the copper foil according to any one of claims 1 to 15.
  17. 　請求項１６に記載の銅張積層板を材料としたフレキシブルプリント配線板。 A flexible printed wiring board made of the copper clad laminate according to claim 16.
  18. 　請求項１７に記載のフレキシブルプリント配線板と、前記フレキシブルプリント配線板で電気的に接続された第１の基板及び第２の基板とを備えた電子機器。 An electronic apparatus comprising: the flexible printed wiring board according to claim 17; and a first substrate and a second substrate electrically connected by the flexible printed wiring board.
PCT/JP2011/076581 2010-11-25 2011-11-17 Rolled copper foil for flexible printed wiring board, copper-clad laminated board, flexible wiring board, and electronic device WO2012070471A1 (en)

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PCT/JP2011/076581 WO2012070471A1 (en) 2010-11-25 2011-11-17 Rolled copper foil for flexible printed wiring board, copper-clad laminated board, flexible wiring board, and electronic device

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001125127A (en) * 1999-10-26 2001-05-11 Citizen Watch Co Ltd Liquid crystal device and connecting method therefor
JP2002167632A (en) * 2000-11-29 2002-06-11 Nippon Mining & Metals Co Ltd Rolled copper foil for flexible printed circuit board and its production method
JP2003096526A (en) * 2001-07-17 2003-04-03 Nippon Mining & Metals Co Ltd Rolled copper foil for copper laminated board, and production method therefor
JP2005317880A (en) * 2004-04-30 2005-11-10 Nikko Metal Manufacturing Co Ltd Metallic material for printed-wiring board
JP2008041972A (en) * 2006-08-08 2008-02-21 Nikko Kinzoku Kk Metal material for printed-wiring board
JP2010239081A (en) * 2009-03-31 2010-10-21 Nippon Mining & Metals Co Ltd Copper foil for printed wiring board
JP2010239095A (en) * 2009-03-31 2010-10-21 Nippon Mining & Metals Co Ltd Copper foil for printed wiring board

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001125127A (en) * 1999-10-26 2001-05-11 Citizen Watch Co Ltd Liquid crystal device and connecting method therefor
JP2002167632A (en) * 2000-11-29 2002-06-11 Nippon Mining & Metals Co Ltd Rolled copper foil for flexible printed circuit board and its production method
JP2003096526A (en) * 2001-07-17 2003-04-03 Nippon Mining & Metals Co Ltd Rolled copper foil for copper laminated board, and production method therefor
JP2005317880A (en) * 2004-04-30 2005-11-10 Nikko Metal Manufacturing Co Ltd Metallic material for printed-wiring board
JP2008041972A (en) * 2006-08-08 2008-02-21 Nikko Kinzoku Kk Metal material for printed-wiring board
JP2010239081A (en) * 2009-03-31 2010-10-21 Nippon Mining & Metals Co Ltd Copper foil for printed wiring board
JP2010239095A (en) * 2009-03-31 2010-10-21 Nippon Mining & Metals Co Ltd Copper foil for printed wiring board

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