JP2016191091A - Rolled copper foil for flexible printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide rolled copper foil excellent in flexibility as well as vibration resistance.SOLUTION: In rolled copper foil, a proportion S/Sof an area S in a rolled surface crystal of grains having a {100} plane within 10° from the rolled surface is 0.2 or higher, with regard to a measurement area Sof the rolled surface, and a proportion S/S of an area Sin the rolled surface of crystal grains having a {811} plane within 3° from the rolled surface is within a range of 0-0.05, with regard to the S.SELECTED DRAWING: None

Description

  The present invention relates to a rolled copper foil for a flexible printed wiring board, and more particularly to a rolled copper foil used for an in-vehicle flexible printed wiring board.

  A flexible printed wiring board (FPC) is obtained by bonding a metal as a conductive layer and a flexible insulating substrate typified by a resin film. In general, a copper foil is used for the conductive layer, and a rolled copper foil having excellent flexibility is used particularly for applications that require flexibility.

  A general FPC manufacturing process is as follows. First, the copper foil is bonded to the resin film. For joining, there are a method of imidizing by applying heat treatment to a varnish applied on a copper foil, and a method of laminating a resin film with an adhesive and a copper foil. The copper foil with a resin film joined by these steps is referred to as CCL (copper-clad laminate). Thereafter, wiring is formed by etching to complete the FPC.

Flexibility required for rolled copper foil for FPC is becoming strict as electronic devices become lighter, shorter, and more functional. It is known that {100} <001> recrystallized texture (Cube recrystallized texture) develops when recrystallized rolled pure copper (for example, Eiichi Furubayashi “Recrystallization and Material Texture” Tsuruho, 2000), a technique for improving the flexibility of rolled copper foil using a Cube recrystallized texture has been proposed in the past. In JP-A-11-286760 (Patent Document 1), the strength of the (200) surface obtained by X-ray diffraction of fine powder copper having the strength (I) of (200) surface obtained by X-ray diffraction of the rolled surface. It has been proposed that the ratio to (I ₀ ) be I / I ₀ > 20. In Patent Document 1, as a method for producing the rolled copper foil, annealing immediately before the final cold rolling is performed under the condition that the average grain size of the recrystallized grains obtained by this annealing is 5 to 20 μm. It is described that the degree of rolling in the final cold rolling is 90% or more.

  Moreover, in the cross-sectional structure of the copper foil in the state where the rolled copper foil is annealed, the ratio (cross-sectional area ratio) of the cross-sectional area of crystal grains penetrating between both surfaces of the copper foil in the thickness direction occupies the entire cross-sectional area. ) Is also known to improve the flexibility of the copper foil. In JP 2009-275290 A (Patent Document 2), in the cross-sectional structure of the copper foil in a state where the rolled copper foil is annealed, the cross-sectional area of the crystal grains penetrating between both surfaces of the copper foil in the plate thickness direction is the whole. A technique for increasing the ratio (cross-sectional area ratio) to the cross-sectional area is disclosed. In order to manufacture such a rolled copper foil, an ingot of tough pitch copper or oxygen-free copper is hot-rolled to a thickness of 18 mm, and further thinned to a thickness of 2.0 mm by cold rolling, and an intermediate sintered Thereafter, cold rolling and annealing are repeated to obtain a thickness of 1.4 to 0.14 mm, and a final sheet thickness of 10 to 33 μm is obtained by final rolling, followed by a final annealing at 130 to 200 ° C. for 30 minutes. It is disclosed.

Japanese Patent Laid-Open No. 11-286760 JP 2009-275290 A

Eiichi Furubayashi, “Recrystallization and Material Structure”, Uchida Otsukuru, 2000

  In an FPC used in an environment subject to frequent vibrations such as in-vehicle applications, the copper foil is fatigued and the conductive layer is easily cracked. Since the electrical characteristics of the FPC deteriorate due to the occurrence and propagation of cracks, cracks do not easily occur even in vibration environments so that they can withstand long-term use of electronic and electrical equipment equipped with FPCs. A copper foil having excellent fatigue resistance is desired. Although the rolled copper foil proposed in the prior art is effective for improving the flex life of the FPC, the fatigue resistance under vibration (hereinafter referred to as “vibration resistance”). There is still room for improvement.

  Therefore, an object of the present invention is to provide a rolled copper foil that is excellent in vibration resistance in addition to flexibility. Moreover, this invention makes it another subject to provide FPC provided with such a rolled copper foil.

  Regarding the cause of cracks on the metal surface, there is the following knowledge. When the metal is repeatedly deformed, protrusions and penetrations are formed on the metal surface. And this protrusion and penetration | invasion are observed as a surface unevenness | corrugation from a cross section. Cracks originate from this unevenness (for example, “Atomology of Material Strength”, lecture / modern metallurgy, material edition 3, Japan Institute of Metals). In view of this, the present inventor considered that it is important to prevent the formation of sharp protrusions or intrusions on the surface of the copper foil in a vibration environment, and studied the solutions for the problem.

  As a result, it has been found that the formation of protrusions and penetrations on the surface of the copper foil is greatly influenced by the crystal orientation, and the vibration resistance is not improved by the technique of increasing the crystal grains as in Patent Document 2. In addition, when the diffraction peak intensity on the (200) plane is increased as in Patent Document 1, the width of protrusion and penetration is increased, so that the vibration resistance is improved to some extent, but even if the plate surface is near the {100} plane. There were places where sharp protrusions and intrusions were formed after the vibration test, and cracks sometimes occurred therefrom. The present inventor has investigated the cause of the occurrence of cracks. As a result, even when the plate surface is in the vicinity of the {100} plane, there are some crystal grains containing crystal rotation, which are in a specific direction from the {100} plane. It has been found that sharp protrusions and intrusions are likely to be formed when it is rotated. And it was found that the vibration resistance is significantly improved by controlling the rotation of crystal grains in a specific direction while controlling the plate surface in the vicinity of the {100} plane. The present invention has been created based on this finding.

In one aspect of the present invention, the ratio S / S ₀ of the rolling surface area S occupied by crystal grains in which the {100} plane is within 10 ° of the rolling surface with respect to the measurement area S ₀ of the rolling surface is 0.2 or more. and, the ratio S ₁ / S of the area S ₁ of the rolling surface of {811} plane to the S crystal grains occupy is within 3 ° from the rolling surface is rolled copper foil in the range of 0 to 0.05.

In one embodiment of the rolled copper foil according to the present invention, the ratio S ₂ / S of the rolled surface area S ₂ occupied by the crystal grains in which the {811} surface with respect to S is within 5 ° from the rolled surface is 0 to 0.00. It is in the range of 05.

  In another embodiment, the rolled copper foil according to the present invention is one or more elements selected from the group consisting of Ag, Sn, Zn, Zr, Cr, Fe, Mg, Si, Ti, Ni and P. In a total of 1 to 500 ppm by mass.

  In yet another embodiment, the rolled copper foil according to the present invention has a surface plated with one or more elements selected from the group consisting of Ni, Co, Cu, Zn, Sn, and Cr. Yes.

  In yet another embodiment, the rolled copper foil according to the present invention is used as a conductor material for a flexible printed wiring board.

  In another embodiment of the rolled copper foil according to the present invention, the flexible printed wiring board is for vehicle use.

  In another aspect, the present invention is a flexible copper clad laminate provided with the rolled copper foil according to the present invention.

  In still another aspect, the present invention is a flexible printed wiring board obtained by processing the flexible copper clad laminate according to the present invention.

  In another aspect of the present invention, the rolled copper foil before recrystallization is any one of the rolled copper foils according to the present invention when recrystallized under any condition of 200 ° C. to 400 ° C. × 30 min. It is the rolled copper foil before recrystallization which satisfy | fills these requirements.

  According to the present invention, a rolled copper foil excellent in vibration resistance in addition to flexibility is provided. The rolled copper foil according to the present invention is particularly useful as a conductor layer of, for example, an in-vehicle FPC.

It is a schematic diagram which shows the mounting state to the jig | tool of the test piece at the time of performing a vibration test with respect to an FPC test piece.

  The copper foil base material used in the present invention is a rolled copper foil. The rolled copper foil is superior to the electrolytic copper foil in that it has high strength, can cope with an environment in which vibration continuously occurs, and has high flexibility. In the present invention, “copper foil” includes copper alloy foil. There is no restriction | limiting in particular as a material of copper foil, What is necessary is just to select suitably according to a use or a required characteristic. The Cu concentration in the copper foil is preferably 99.8% by mass or more, more preferably 99.85% by mass or more, and more preferably 99.9% by mass or more for reasons of ensuring high conductivity. Is more preferable. However, even if the Cu concentration is too high, it leads to an increase in cost, so 99.999 mass% or less is preferable, and 99.995 mass% or less is more preferable. Since the oxygen concentration in the copper foil leads to an increase in cuprous oxide and leads to the suppression of the development of the cube orientation, it is preferably less than 0.01% by mass, preferably 0.005% by mass or less, For example, it can be 0.0001 mass% or more and less than 0.01 mass%. As a copper foil satisfying such conditions, for example, oxygen-free copper (OFC) standardized in JIS-H3510 or JIS-H3100 can be used.

In addition, one or more elements selected from the group consisting of Ag, Sn, Zn, Zr, Cr, Fe, Mg, Si, Ti, Ni, and P can be added to the copper foil. As a result, an effect of increasing S / S ₀ is obtained. Although it is not intended that the present invention be limited by theory, it is difficult to develop a {100} <001> recrystallization texture because dynamic recrystallization occurs when the purity of the copper foil is high. On the other hand, it is considered that when these elements are added, dynamic recrystallization is suppressed and a {100} <001> recrystallization texture is easily developed. In order to exhibit the strength improvement effect and the S / S ₀ increase effect significantly, the total concentration of these elements is preferably 1 mass ppm or more, more preferably 5 mass ppm or more, and more preferably 10 mass ppm. More preferably, it is more preferably 50 ppm by mass or more, still more preferably 100 ppm by mass or more. On the other hand, if the total concentration of these elements becomes too high, the extensibility and workability may deteriorate, so the total concentration of these elements is preferably 500 mass ppm or less, and 400 mass ppm or less. Is more preferable, and it is still more preferable to set it as 300 mass ppm or less.

Illustratively, a copper alloy to which Sn, Ag, Zr, Ti, Fe, Zn, Ni, Si, Cr, Zr, or the like is added can be used. Among them, Ag, Sn, be added in an amount of Zr and the content below 500 ppm by weight in total of one or more elements selected from the group of Ti is preferred from the viewpoint of increasing the S / S _0. When the content of Ag, Sn, Zr and Ti exceeds 500 mass ppm in total, the strength is further improved, but the elongation is lowered and the workability may be deteriorated. More preferably, the total content of Ag, Sn, Zr and Ti is 300 ppm by mass or less. The lower limit of the total content of Ag, Sn, Zr and Ti is not particularly limited, but for example, 10 mass ppm can be set as the lower limit. If the total content of Ag, Sn, Zr, and Ti is less than 10 ppm by mass, the effect may be reduced, and it may be difficult to control the content because the content is small. Preferably, the total amount of Ag, Sn, Zr and Ti is 30 ppm by mass or more, more preferably 40 ppm by mass or more, and most preferably 50 ppm by mass or more.

  Similarly, when the copper alloy described above is used as the copper foil according to the present invention, the oxygen concentration in the copper foil is preferably less than 0.01% by mass, more preferably 0.005% by mass or less. Although a copper alloy is used, it is acceptable that the oxygen concentration in the copper foil is somewhat high. Specifically, the oxygen concentration is allowed to be 0.05% by mass or less, and typically 0.01 to 0.03% by mass. For this reason, the tough pitch copper prescribed | regulated to JIS-H3100, for example can also be used as a copper raw material.

  There is no restriction | limiting in particular in the thickness of copper foil, What is necessary is just to select suitably according to a required characteristic. Generally, it is 1 to 300 μm, but when used as a conductor layer of a flexible printed wiring board, it is possible to obtain higher flexibility and vibration resistance when the copper foil is thinned. From such a viewpoint, the thickness of the copper foil is generally 2 to 50 μm, typically about 5 to 35 μm. However, in applications where large current flows and heat generation due to energization is particularly hated, such as in-vehicle use, the copper foil should be relatively thick from the viewpoint of energizing without disconnection while ensuring conductivity and heat dissipation. Therefore, in such a case, the thickness is preferably 35 μm or more. However, if the thickness is excessively large, it may be difficult to remove the conductor layer by etching. Therefore, the thickness is preferably 300 μm or less, and more preferably 150 μm or less.

In one embodiment, the rolled copper foil according to the present invention has a ratio S / S ₀ of the area S of the rolled surface occupied by crystal grains whose {100} plane is within 10 ° from the rolled surface with respect to the measured area S ₀ of the rolled surface. It has a crystal orientation of 0.2 or more. S ₀ is set to 1 mm ² or more so that it can be calculated accurately even if the crystal grain size is large. Thus, the flexibility can be improved by increasing the ratio of the crystal grains whose {100} plane is within 10 ° from the rolling plane. S / S ₀ is preferably 0.3 or more, more preferably 0.4 or more, even more preferably 0.5 or more, still more preferably 0.6 or more, and even more preferably It is 0.7 or more, still more preferably 0.8 or more, and can be controlled to 0.2 to 0.9, for example.

  The higher the ratio of crystal grains whose {100} plane is within 10 ° from the rolling surface, the better the flexibility. However, in order to combine excellent vibration resistance, the crystal grains can be within 10 °. It is important that does not rotate in a particular direction. Specifically, when the crystal grains are rotated in a direction perpendicular to the <011> orientation (rotating with <011> as the rotation axis), the vibration resistance tends to be deteriorated. And the flexibility becomes worse as the angle of rotation is larger (closer to 10 °). When <011> is rotated about 10 ° from the <100> orientation about the rotation axis, the <811> orientation is obtained. Therefore, the ratio of the grains having the {811} plane within 3 ° from the rolling plane should be as low as possible with respect to the area S of the rolling plane occupied by the grains having the {100} plane within 10 ° from the rolling plane. Thus, vibration resistance can be significantly improved.

Therefore, in one embodiment of the rolled copper foil according to the present invention, the ratio S ₁ / S of the area S ₁ of the rolled surface occupied by the crystal grains having the {811} plane with respect to S within 3 ° from the rolled surface is 0 to 0. The crystal orientation is in the range of 0.05. S ₁ / S is preferably 0.04 or less, more preferably 0.03 or less, even more preferably 0.02 or less, even more preferably 0.01 or less, and even more preferably It is 0.005 or less, and can be controlled to 0.001 to 0.05, for example.

From the viewpoint of improving the vibration resistance, not only the ratio of crystal grains whose {811} plane is within 3 ° from the rolling plane, but also the ratio of crystal grains whose {811} plane is within 5 ° from the rolling plane. It is more desirable to reduce it. Accordingly, in one embodiment, the rolled copper foil according to the present invention has a ratio S ₂ / S of the area S ₂ of the rolled surface occupied by crystal grains in which the {811} plane with respect to S is within 5 ° from the rolled surface is 0 to 0. The crystal orientation is in the range of 0.05. S ₂ / S is preferably 0.04 or less, more preferably 0.03 or less, even more preferably 0.02 or less, even more preferably 0.01 or less, and even more preferably It is 0.005 or less, and can be controlled to 0.001 to 0.05, for example.

Strictly speaking, among the crystal grains whose {811} plane is within 3 ° or within 5 ° from the rolling plane, there may be crystal grains whose {100} plane is not within 10 ° from the rolling plane, Considering this, since it is preferable that the {811} plane has less crystal grains within 3 ° or 5 ° from the rolling surface, in the present invention, the area ratio is defined as S ₁ / S or S ₂ / S. It is said.

In the present invention, the area S of the rolling surface occupied by crystal grains whose {100} plane is within 10 ° from the rolling surface, and the area S _{1 of the} rolling surface occupied by crystal grains whose {811} plane is within 3 ° from the rolling surface. , And the area S _{2 of the} rolled surface occupied by the crystal grains whose {811} plane is within 5 ° from the rolled surface, respectively, after the rolled surface is electropolished and washed, then the EBSD method (backward electron beam) using OIM software is used. The crystal orientation can be calculated by a scattering analysis method).

  The copper foil which concerns on this invention can be manufactured as follows, for example. First, a copper raw material such as electrolytic copper, oxygen-free copper, tough pitch copper or the like is melted, and an alloy element is added as necessary, and then the molten metal is cast to produce an ingot having a thickness of about 100 to 300 mm. Adjustment of the oxygen concentration in the melting step can be performed by techniques known to those skilled in the art, such as carbon sealing of the molten metal and release to the atmosphere. Then, after performing hot rolling, cold rolling and annealing are repeated to obtain a copper foil base material after final cold rolling. The higher the rolling reduction of the final cold rolling, the easier the {100} plane develops by the subsequent recrystallization annealing. Therefore, the reduction degree of the final cold rolling is 93% or more, more preferably 95% or more. When manufacturing a copper foil having a large thickness, it tends to be impossible to ensure a large reduction ratio in the final cold rolling (because it is difficult to perform annealing in a state where the plate thickness is thick). Therefore, in the case of a copper foil having a thickness of 35 μm or more after the final cold rolling, it is preferable that the reduction ratio of the final cold rolling is 98% or less in consideration of actual ease of manufacture.

However, S ₁ and S ₂ cannot be lowered even if the rolling reduction during the final cold rolling is increased. To lower the values of S ₁ and S ₂ , it is necessary to reduce the shear deformation. In general, the shear deformation is caused by friction on the surface of the copper foil during rolling and due to a difference in path between the surface and the inside.

In order to increase the workability of the final cold rolling, it is necessary to roll from a copper plate having a relatively large thickness. At this time, if a roll having a small diameter is used at a stage where the plate thickness is large, the path difference between the inside and the surface becomes large. Therefore, in order to reduce the path difference, it is effective to increase the diameter of the roll. On the other hand, when a roll having a large diameter is used when the plate thickness is small, the contact area between the roll and the surface of the copper plate is increased, and the surface friction is increased so that shearing easily occurs. Therefore, in order to reduce S ₁ and S ₂ , it is preferable to suppress shear deformation by changing the roll diameter stepwise according to the plate thickness. Specifically, when the plate thickness before passing through the roll is 1 mm or more, it exceeds 100 mmΦ, when the plate thickness before passing through the roll is 0.1 mm or more and less than 1 mm, it exceeds 60 mmΦ or less than 100 mmΦ, and when the plate thickness before passing through the roll is less than 0.1 mm, it is 30 mmΦ or more. It is preferable to use a roll having a diameter of 60 mm or less. When the plate thickness before passing through the roll is 1 mm or more, it is 105 mm to 130 mmΦ, and when the plate thickness before passing through the roll is 0.1 mm or more and less than 1 mm, it is 80 mm to 100 mmΦ. If the thickness is less than 0.1 mm, it is more preferable to use a roll of 30 mmΦ to 50 mmΦ. The roll diameter used when the plate thickness before passing through the roll is 1 mm or more, the roll diameter used when the plate thickness before passing through the roll is 0.1 mm or more and less than 1 mm, and the plate thickness before passing through the roll is 0.00. The roll diameter used when the diameter is less than 1 mm preferably has a difference of 10 mm or more, and more preferably has a difference of 20 mm or more.

Next, the rolled copper foil according to the present invention satisfying the above-described S / S ₀ and S ₁ / S, and preferably S ₂ / S is obtained by recrystallization annealing of the copper foil base material. Preferable annealing conditions include conditions of heating to 200 to 400 ° C. for 15 to 120 minutes. Annealing is preferably performed in an inert gas atmosphere such as nitrogen or Ar for the reason of preventing oxidation. It is also possible to anneal in a vacuum. It becomes possible to raise S significantly by annealing at 200 degreeC or more for 30 minutes or more. Even if the annealing temperature is too high, it is inconvenient, and the effect of lowering S ₁ and S ₂ can be obtained by setting it to 400 ° C. or lower. A longer annealing time is advantageous for the development of the {100} plane, and it is preferable to anneal for 0.5 hour or longer. However, it is not necessary to anneal excessively, and the production efficiency is also lowered. Therefore, it is preferably 2 hours or less, and more preferably 1 hour or less.

In other words, according to the present invention, it is the state before recrystallization (the state after final cold rolling), and heat treatment is performed at 200 to 400 ° C. for 30 minutes, so that S / S ₀ and S ₁ / S Further, a copper foil having the property that, desirably, S ₂ / S can be a rolled copper foil after recrystallization according to the present invention satisfying the preferred range described above is provided.

  The surface of the rolled copper foil according to the present invention includes one or more elements selected from the group consisting of Ni, Co, Cu, Zn, Sn and Cr on the surface in order to adhere a resin such as polyimide. Plating may be performed. The plating is generally called a roughening treatment, and includes Cu plating, Cu—Ni alloy plating, Cu—Co alloy plating, Ni—Co—Cu alloy plating, Ni—Sn alloy plating, Ni—Co—Cu—Zn alloy. An example is plating.

  A flexible copper clad laminate (FCCL) can be produced by laminating and bonding the rolled copper foil according to the present invention on one or both sides of a flexible insulating substrate made of polyester, polyimide, or the like. As an adhesion method, an adhesive made of a thermosetting resin such as epoxy is used, and a copper foil and a polyimide resin film are bonded to each other and heat treatment is performed, or a varnish containing polyamic acid which is a precursor of a polyimide resin Is coated on a copper foil and cured by heating to form a polyimide film on the copper foil. When laminating copper foil on both sides, after forming a single-sided copper clad laminate, there are a method of crimping the copper foil layer by hot pressing, and a method of sandwiching a polyimide film between two copper foil layers and crimping by hot pressing. is there. These heat treatments are generally carried out at 200 to 450 ° C. for 1 to 150 minutes. There is also a method of laminating a copper foil and a resin with an adhesive without going through a heat treatment step.

  As described above, in the FCCL manufacturing process, heat treatment is often performed for bonding the insulating substrate and the copper foil. Therefore, the recrystallization annealing process after the final cold rolling described above can also be used as the heat treatment. Yes, if the heat treatment in the manufacturing process of FCCL is not suitable as the recrystallization annealing process of copper foil, it is preferable to perform recrystallization annealing before producing FCCL. Once recrystallized, the crystal structure does not change even if heat treatment is performed after recrystallization annealing.

  It is possible to manufacture a flexible printed wiring board (FPC) by forming wiring according to a known procedure using the FCCL according to the present invention as a material. For example, apply an etching resist to the copper foil surface of the FCCL only on the necessary part as the conductor pattern, spray the etching solution onto the copper foil surface to remove the unnecessary copper foil, form the conductor pattern, and then peel off the etching resist -The method of removing and exposing a conductor pattern is mentioned. After forming the conductor pattern, it is common to apply a protective coverlay film. Such FPCs are FPCs used for movable parts in hard disks, hinge parts and slide sliding parts of mobile phones, printer head parts, optical pickup parts, movable parts of notebook PCs, etc. in electronic and electrical equipment. To do. In particular, the FPC according to the present invention is suitable as a vehicle-mounted, wearable device, and automatic machine control FPC that is subjected to severe repeated deformation and requires vibration resistance.

  EXAMPLES 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.

<Manufacture of rolled copper foil>
In Examples 1, 3 to 5, 9 to 23 and Comparative Examples 1 to 3 to 4, electrolytic copper and an alloy element corresponding to the test number shown in Table 1 were vacuum-melted and then cast in an inert atmosphere. Copper and copper alloy ingots having the compositions shown in Table 1 were prepared. In Examples 2, 6 to 8 and Comparative Example 2, electrolytic copper and an alloy element corresponding to the test number in Table 1 were dissolved in the air, and then cast in an air atmosphere to have the compositions shown in Table 1 and copper. An alloy ingot was prepared. Those dissolved in the atmosphere contained several hundred ppm by mass of oxygen corresponding to tough pitch copper, and those dissolved in vacuum had an oxygen content of less than 10 ppm by mass corresponding to oxygen-free copper.

  Subsequently, after each ingot was hot-rolled, cold rolling and annealing were repeated, and the final cold rolling was performed at the rolling reduction shown in Table 1 to adjust the thickness to 35 μm. In the final cold rolling, the roll diameter used for rolling was changed as shown in Table 1 according to the plate thickness before passing through the roll. Finally, recrystallization annealing was performed for 30 minutes at each temperature shown in Table 1 under a nitrogen atmosphere to obtain each rolled copper foil.

<Manufacture of FCCL and crystal orientation analysis>
For each of the obtained rolled copper foils, two pieces were cut into a predetermined size and subjected to a roughening treatment with a thickness of 50 μm on one side, and then the temperature of 280 ° C. was set so that the roughened surface became a bonding surface. Were laminated on the front and back of a polyimide film having a thickness of 50 μm under the lamination condition of hot pressing for 1 hour to prepare a double-sided FCCL. The plating composition during the roughening treatment in each test example was as shown in Table 1. Thereafter, all the copper foil on one side is removed by etching to form a single side FCCL, and the rolled surface of the obtained single side FCCL is subjected to surface cleaning by electrolytic polishing, and then the EBSD method using OIM software (TSL Solutions) (manufactured by JEOL Ltd.) Crystal orientation analysis was performed by JXA8500F), S, S ₁ and S ₂ described above were measured, and S / S ₀ , S ₁ / S and S ₂ / S were obtained, respectively. The measurement area S ₀ of the rolled surface was 1 mm ² (1 mm × 1 mm). The measurement was performed twice, and the average value was taken as the measured value.

<Manufacture of FPC>
Using each of the obtained rolled copper foils, a single-sided FCCL was manufactured in the same procedure as described above, and then 5 lines and spaces of 0.3 mm × 0.3 mm linear circuits were formed by etching with a length of 120 mm, Finally, a polyimide coverlay film having a thickness of 50 μm was laminated on both surfaces by hot pressing at a temperature of 180 ° C. for 1 hour to prepare FPC test pieces each having a length of 110 mm and a width of 12 mm.

<IPC bending test>
The flexibility of each FPC test piece obtained above was evaluated using an IPC bending tester manufactured by Shin-Etsu Engineering Co., Ltd. The FPC was fixed so that the ridge line of the bent portion was orthogonal to the wiring direction, and the slide was repeatedly slid under the conditions of a bending radius: 2.5 mm, a stroke: 20 mm, a bending speed: 900 rpm, and a test temperature: 25 ° C. During the bending test, the progress of fatigue cracks in the copper foil circuit was monitored by increasing the electric resistance, and the number of bendings until the electric resistance of the circuit increased by 10% from the initial value was measured.
Flexibility was evaluated according to the following criteria.
◎ = In all circuits, the rate of increase in resistance is over 10% even if it exceeds 100,000 times. ○ = In the case of one or more circuits, the rate of increase in resistance exceeds 10% in the case of more than 50,000 times and less than 100,000 times. Only one circuit is less than 50,000 times and the resistance increase rate exceeds 10%. X = Two or more circuits are 50,000 times or less and the resistance increase rate exceeds 10%.

<Vibration test>
Similarly, as shown in FIG. 1, each FPC test piece obtained by the same procedure as described above is a fixing jig having a radius of curvature (r) of 1 mm, and the test piece is moved from the fixing jig in the longitudinal direction (linear circuit). (Same as the direction of) was set so as to protrude 20 mm. Next, vibration was applied in the thickness direction of the FPC along IEC-60068-2-53. The vibration conditions and temperature cycle conditions were as follows. During the vibration test, the progress of fatigue cracks in the copper foil circuit was monitored by increasing the electrical resistance, and the time until the electrical resistance of the circuit increased by 10% from the initial value was measured.
(Vibration conditions)
・ Amplitude 1mm
・ Frequency: Frequency changes periodically in the range of 5 to 170 Hz (sinusoidal vibration with 5 minutes as one cycle)
・ Vibration time: 200 hours (temperature cycle conditions)
6 steps of holding at 25 ° C. for 1 hour → temperature reduction → −30 ° C. for 2 hours → temperature increase → 85 ° C. for 2 hours → temperature reduction are repeated in 8 hours per cycle.
Vibration resistance was evaluated according to the following criteria.
A: More than 200 hours (In 200 hours, the electrical resistance of all circuits did not increase by 10% from the initial value.)
○ = 150 hours to 200 hours (The electric resistance of at least one circuit increases by 10% from the initial value in 150 to 200 hours)
Δ = less than 150 hours (only one circuit has less than 150 hours and the electric resistance increases by 10% from the initial value)
X = less than 150 hours (two or more circuits are less than 150 hours, and the electric resistance increases by 10% from the initial value)

The test results are shown in Table 1. In Comparative Example 1, since the total refining degree of the final rolling was a manufacturing condition, the Cube recrystallization texture did not develop, and S / S ₀ became small. Therefore, both flexibility and vibration resistance were poor. Since Comparative Examples 2 to 4 were improved to production conditions with a high total workability of the final rolling, the Cube recrystallized texture developed, but the {811} plane was removed from the rolled surface by the crystal rotation that occurred during the final cold rolling. The number of crystal grains within 3 ° and within 5 ° increased, and S ₁ / S and S ₂ / S were high. For this reason, the flexibility and vibration resistance were improved as compared with Comparative Example 1, but the effects were limited.

On the other hand, in Examples 1 to 23, the total degree of work of the final rolling was sufficiently high, and the roll diameter of the final rolling was set to the manufacturing conditions shown in Table 1, so that in addition to the development of the Cube recrystallization texture In the final cold rolling, crystal rotation was suppressed, S ₁ / S was reduced, and the flexibility and vibration resistance were significantly improved. In particular, in Examples 1 to 16 and 21 in which S ₂ / S was also controlled to be small, the improvement in flexibility and vibration resistance was remarkable. This is presumably because the rolled copper foil according to the present invention is difficult to form sharp protrusions and intrusions on the surface of the copper foil, while wide protrusions and intrusions are formed overall.

Claims (9)

The ratio S / S ₀ of the area S of the rolled surface occupied by the crystal grains whose {100} plane is within 10 ° of the rolled surface with respect to the measured area S ₀ of the rolled surface is 0.2 or more, and {811 relative to S } The rolled copper foil in which the ratio S ₁ / S of the area S ₁ of the rolled surface occupied by crystal grains whose surface is within 3 ° from the rolled surface is in the range of 0 to 0.05. _2. The rolled copper according to claim 1, wherein the ratio S ₂ / S of the area S ₂ of the rolled surface occupied by the crystal grains whose {811} plane with respect to S is within 5 ° from the rolled surface is in the range of 0 to 0.05. Foil.   1 or 500 ppm in total containing one or more elements selected from the group consisting of Ag, Sn, Zn, Zr, Cr, Fe, Mg, Si, Ti, Ni and P The rolled copper foil described in 1.   The rolled copper foil according to any one of claims 1 to 3, wherein the surface is plated with one or more elements selected from the group consisting of Ni, Co, Cu, Zn, Sn and Cr. .   The rolled copper foil as described in any one of Claims 1-4 used as a conductor material of a flexible printed wiring board.   The rolled copper foil according to claim 5, wherein the flexible printed wiring board is for vehicle use.   The flexible copper clad laminated board provided with the rolled copper foil as described in any one of Claims 1-6.   A flexible printed wiring board obtained by processing the flexible copper-clad laminate according to claim 7.   It is the rolled copper foil before recrystallization, Comprising: When it recrystallizes on the conditions in any one of 200 to 400 degreeC * 30min, the requirements for the rolled copper foil as described in any one of Claims 1-6 are satisfy | filled. Rolled copper foil before recrystallization.