JP2007262493A - Material for flexible printed board and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide copper clad laminate type material for a flexible printed board, which is manufactured by an electrolytic copper plating method and exhibits remarkably excellent flexibility immediately after being manufactured (plated) and is hardly broken or cracked when being folded in high density wiring, and to provide a method of manufacturing the material. <P>SOLUTION: The copper clad laminate type material for the flexible printed board is hardly broken or cracked when being folded in high density wiring and is manufactured by the electrolytic copper plating method. The material is obtained by laminating a copper layer on a plastic film by the electrolytic copper plating method and after that, heat-treating the resultant plastic film at a fixed temperature for a fixed period of time to control the crystallite size of copper to obtain excellent folding resistance of copper. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a copper laminate type flexible printed circuit board material by an electrolytic copper plating method and a method for producing the same.

As electronic devices become smaller, lighter, more functional, more multifunctional, and more densely packed, printed wiring boards have been reduced by reducing the width of conductors and between conductors, increasing the number of layers, making them flexible, and reducing the thickness of substrates. Densification is progressing rapidly and it is developing into a material for flexible printed circuit boards.
Conventionally, a material for a flexible printed circuit board having a three-layer structure in which a copper foil as a conductor layer is bonded to a polyimide film via an adhesive layer is known (see Patent Document 1). In this three-layer structure type flexible printed circuit board material, the heat resistance of the adhesive used is inferior to that of a polyimide film, so that there is a problem that the dimensional accuracy after processing decreases, and the thickness of the copper foil used is usually Since the thickness is 10 μm or more, there is a disadvantage that patterning for high-density wiring with a narrow pitch is difficult. Furthermore, when the IC is mounted, the adhesive is melted or pyrolyzed with respect to the IC heated to a high temperature, so that the IC bump and the lead on the flexible printed circuit board material can be accurately connected. Absent. Therefore, when mounting an IC, it is common to make a hole by punching the IC mounting position by a method such as punching so that no adhesive is interposed under the IC chip.
On the other hand, a copper layer as a conductor layer was formed on a polyimide film by a wet electrolytic copper plating method or a dry plating method (for example, a vacuum deposition method, a sputtering method, an ion plating method, etc.) without using an adhesive. Layered structure type flexible printed circuit board materials are known (see Patent Document 2 and Patent Document 3). The copper laminated type flexible printed circuit board materials by electrolytic copper plating without using adhesives do not have adhesives, so they do not drill on the film surface as described above during IC mounting. It is possible to mount an IC. In addition, since the two-layer structure type flexible printed circuit board material can easily make the copper layer thinner than 10 μm, high-density wiring of the flexible printed circuit board material is possible.
Usually, in flexible printed circuit board materials used for bending applications such as electronics equipment, high-purity metal foil or other low recrystallization temperature metal foil is used as the metal foil of the metal foil layer in order to improve flexibility, With these metal foils, the recrystallization temperature is low, recrystallization occurs due to strain energy due to deformation, strain energy is released as appropriate, high flexibility is obtained, grain boundaries and cracks are suppressed, and excellent flexibility Is known (see Patent Document 4).
However, the above-described method for improving the flexibility is for improving the flexibility of the flexible printed circuit board material using the metal foil. In the case of the copper laminated type flexible printed circuit board material by the electrolytic copper plating method, Although not applicable, in the case of electrolytic copper plating, it is superior to flexible printed circuit board materials using the above metal (copper) foil by growing the crystallite size of copper sufficiently large by optimizing the plating solution composition, etc. Flexibility can be obtained.
This bendability can be measured by a bend resistance test described in JIS C5016. However, when the bendability is required as a component of an electronic device, the above bend resistance test is required for a substrate having a conductive layer on both sides. In applications where bending is repeatedly performed on a substrate having a conductive layer on one side, a level of 300 times or more is required in the above folding resistance test.
However, as a result of intensive studies by the inventors, the copper crystallite size (200 plane) immediately after electrolytic copper plating of the copper laminated type flexible printed circuit board material by the electrolytic copper plating method is less than 200 angstroms. It has been found that copper is poor in bending resistance and must be left for 10 days or more in natural standing for use in bending applications.
Japanese Patent Laid-Open No. 07-202417 Japanese Patent Laid-Open No. 2002-20898 Japanese Patent Laid-Open No. 2003-321796 JP 2001-168480 A

  The object of the present invention is to control copper crystallite size and to have good copper crease resistance even immediately after plating, thereby preventing copper breakage and cracking at the time of bending in high-density wiring by electrolytic copper plating. It is an object of the present invention to provide a laminated type flexible printed circuit board material and a method for manufacturing the same.

  Means for solving the above-described problems of the present invention are as follows.

  The flexible printed circuit board material of the present invention is a flexible printed circuit board material obtained by laminating a copper layer having a thickness of 4 μm or more and 12 μm or less on one surface of a plastic film by an electrolytic copper plating method. A flexible printed circuit board material having a folding resistance index A of 300 times or more within 240 hours after electrolytic copper plating.

  The material for a flexible printed circuit board of the present invention is a material for a flexible printed circuit board in which a copper layer having a thickness of 4 μm or more and 12 μm or less is laminated on both surfaces of a plastic film by an electrolytic copper plating method, A flexible printed circuit board material having a bending index B of 30 times or more within 240 hours after electrolytic copper plating.

  According to a preferred aspect of the flexible printed circuit board material of the present invention, the copper crystallite size (200 planes) of the copper layer within 240 hours after electrolytic copper plating is 200 angstroms or more.

  According to the preferable aspect of the flexible printed circuit board material of this invention, the said plastic film is a polyimide film or a polyethylene terephthalate film, The thickness is 12-40 micrometers.

  According to a preferred embodiment of the flexible printed circuit board material of the present invention, the flexible printed circuit board material is formed by forming a nickel / chromium alloy layer on the plastic film and then forming a copper layer thereon by electrolytic copper plating. It is formed by stacking.

  Moreover, the manufacturing method of the material for flexible printed circuit boards of this invention is the manufacturing method of the copper laminated type flexible printed circuit board material by an electrolytic copper plating method. And heat-treating at a temperature of 60 to 200 ° C. for 1 to 15 hours.

  Moreover, the manufacturing method of the material for flexible printed circuit boards of this invention is the manufacturing method of the copper laminated type flexible printed circuit board material by an electrolytic copper plating method. ° C) is 220 ≧ T, the heat treatment time t (minutes) is 0.1 <t <10, and the relationship between the heat treatment temperature T and the heat treatment time t satisfies the range of T> 95-250 Logt. It is a manufacturing method of the material for flexible printed circuit boards characterized by heat-processing on temperature conditions.

  In the present invention, the plastic film substrate is suitably used for a long plastic film substrate. The long length is usually used for a film substrate having a width of 5 m or less and a length of 10 m or more.

  ADVANTAGE OF THE INVENTION According to this invention, the copper laminated type flexible printed circuit board material by the electrolytic copper plating method with which the disconnection at the time of bending in a high-density wiring and a crack are hard to generate | occur | produce is obtained. The copper laminated type flexible printed circuit board material by the electrolytic copper plating method according to the present invention can be used immediately after manufacture (plating), such as an electronic computer, terminal equipment, telephone, communication equipment, measurement control equipment, camera, watch, automobile, supply. It can be used in all fields of electronics such as equipment, home appliances, aircraft instruments and medical equipment, and contributes to the suppression of conductor disconnection and breakage and the increase in the density of circuit boards.

  The flexible printed circuit board material of the present invention is obtained by laminating a copper layer having a thickness of 4 μm or more and 12 μm or less on one or both surfaces of a plastic film by an electrolytic copper plating method.

  And the flexible printed circuit board material of the present invention is a flexible printed circuit board material obtained by laminating a copper layer having a thickness of 4 μm or more and 12 μm or less on one surface of a plastic film by an electrolytic copper plating method, A flexible printed circuit board material having a folding index A of 300 times or more within 240 hours after decopper plating of a copper layer, more preferably, the copper crystallite size (200 planes) of the copper layer is 200 angstroms or more. A method for evaluating the folding resistance index A will be described later.

  Moreover, in this invention, it is the material for flexible printed circuit boards formed by laminating | stacking a copper layer with a thickness of 4 micrometers or more and 12 micrometers or less respectively on both surfaces of a plastic film by the electrolytic copper plating method, 240 after electrolytic copper plating of the said copper layer The flexible printed circuit board material is characterized in that the bending resistance index B within 30 hours is 30 times or more, and more preferably, the copper crystallite size (200 planes) of the copper layer is 200 angstroms or more. A method for evaluating the folding resistance index B will be described later.

  Examples of the plastic film used in the present invention include polyesters such as polyethylene terephthalate, polyethylene-2,6-naphthalate, and polyethylene-α, β-bis (2-chlorophenoxyethane-4,4′-dicarboxylate). , Polyphenylene sulfide, polyethersulfone, polyetheretherketone, aromatic polyamide, polyarylate, polyimide, polyamideimide, polyetherimide, polyparazic acid, polyoxadiazole, and plastic films composed of halogenated or methyl group-substituted products thereof Is mentioned. Moreover, the plastic film containing the copolymer of these polymers and another organic polymer may be sufficient.

  Known additives such as lubricants and plasticizers may be added to these plastic films. Among these plastic films, a polyimide film is excellent in heat resistance during solder mounting and is particularly preferably used for the application of the present invention. Further, the polyethylene terephthalate film is inexpensive and easy to handle unless it is mounted by soldering.

In addition, the thickness of the plastic film as the substrate is usually about 4 to 125 μm, but in the case of the present invention, a plastic film having a thickness of 12 to 40 μm is suitable. If the thickness of the plastic film is less than 12 μm, wrinkles may occur in the sputtering process before copper plating, and flatness may be poor. On the other hand, if the thickness is greater than 40 μm, the flexibility of the copper plating layer formed on the plastic film may be lowered.
In the present invention, prior to forming a thicker copper layer on the plastic film by electrolytic copper plating, the metal deposited layer can be formed on the plastic film by vacuum deposition or sputtering. The metal constituting the metal vapor deposition layer is preferably a metal such as copper, gold, silver, nickel, chromium, molybdenum and titanium, more preferably copper, nickel and chromium, more preferably copper and nickel / chromium alloy, As a result, it is possible to form a metal vapor deposition layer having low resistance and high flexibility.

  In the present invention, the metal vapor deposition layer may be a single layer, but in order to increase the adhesion between the copper layer and the plastic film, it is preferable to form the first layer with a nickel / chromium alloy and form the second layer with copper. Further, layers having other functions may be stacked.

  The thickness of the metal vapor deposition layer provided on the plastic film by vapor deposition or sputtering is preferably 10 to 3000 angstrom, more preferably 20 to 2500 angstrom, and further preferably 30 to 2000 angstrom. When the thickness of the deposited metal layer is less than 10 angstroms, the film is likely to elute after the electrolytic copper plating process, and when it is thicker than 3000 angstroms, wrinkles are generated after the electrolytic copper plating process or the productivity speed is reduced. Problems can occur.

  The resistance value of the surface of the metal vapor deposition layer is preferably 1.0 Ω / cm or less (resistance value measured at a distance of 1 cm between terminals is 1.0 Ω / cm or less) because it is easy to perform electrolytic copper plating. Is 0.5 Ω / cm or less.

A thicker copper layer can be formed on the metal deposition layer by electrolytic copper plating. In the electrolytic copper plating step, after performing a degreasing or acid activation treatment or a metal strike for improving the adhesion between the metal vapor deposition layer and the plating layer, each step of electrolytic copper plating can be performed. When the electrolytic copper plating is started immediately after depositing the metal deposition layer, degreasing and acid activation treatment and metal strike may be omitted. The current density supplied to the metal vapor deposition layer is preferably 0.2 to 10 A / dm ² , more preferably 0.5 to 5 A / dm ² .

  In the present invention, the thickness of the copper layer formed by electrolytic copper plating is preferably 2 to 30 μm, more preferably 4 to 12 μm. When the thickness of the copper layer is less than 4 μm, the reliability of the copper layer may not be sufficient. In addition, when the thickness of the copper layer exceeds 12 μm, the film formation takes time and the economy is inferior, and the end portion of the circuit pattern is easily etched during etching, and there is a risk of disconnection due to bending. It may not be preferable in terms of quality.

  In the present invention, the conditions for electrolytic copper plating differ depending on the composition of the plating bath, the current density, the bath temperature, the stirring conditions, etc., but are not particularly limited.

  In the present invention, a copper laminate type flexible printed circuit board material by an electrolytic copper plating method in which a copper layer having a thickness of 4 μm or more and 12 μm or less is laminated on one surface of a plastic film, the copper layer being electrolyzed Within 240 hours after copper plating, the folding index A described later is 300 times or more, and the copper laminate type flexible printed circuit board material by the electrolytic copper plating method has the folding index A within the above range. Therefore, a specific heat treatment is preferably applied. The heat treatment is applied in a nitrogen atmosphere or an air atmosphere.

  In addition, it is a material for a flexible printed circuit board in which a copper layer having a thickness of 4 μm or more and 12 μm or less is laminated on both surfaces of a plastic film by electrolytic copper plating, and the folding resistance of the copper layer within 240 hours after electrolytic copper plating. In the flexible printed circuit board material characterized in that the index B is 30 times or more, a specific heat treatment is suitably applied so that the folding resistance index B is within the above range. The heat treatment is applied in a nitrogen atmosphere or an air atmosphere.

  Next, the manufacturing method of the flexible printed circuit board material of this invention is demonstrated.

  One of the methods for producing the flexible printed circuit board material of the present invention is that after electrolytic copper plating, it is preferably wound up, and the wound material is put into a heat treatment step using an oven or a dryer within 120 hours. It is. The heat treatment temperature is suitably about 60 to 200 ° C. When the heat treatment temperature is 60 ° C. or lower, the heat treatment effect may not be sufficiently obtained. Moreover, when the heat treatment temperature is 60 ° C. or lower, sufficient heat treatment cannot be performed on the core of the wound film-like material, and as a result, it may be difficult to control the crystallite size of copper. Further, if the heat treatment temperature is 200 ° C. or higher, it may affect copper oxidation, dimensional change of the plastic film, adhesion between the plastic film and the copper layer, and the like.

  In general, the heat treatment time is preferably about 1 to 15 hours. When the heat treatment time is 1 hour or less, it may be difficult to control the crystallite size of the copper at the center of the wound film. Further, if the heat treatment time is 15 hours or longer, the dimensional change rate or flatness of the plastic film (vertical wrinkles or horizontal wrinkles) may be affected.

  In the present invention, as another preferred method, in the copper laminated type flexible printed circuit board material by the electrolytic copper plating method, after electrolytic copper plating, it is continuously subjected to a heat treatment process using an oven or a dryer before winding. For example. Since the processing is performed continuously (in-line), it is not realistic to process for a long time. Conversely, if the time is too short, it may be difficult to control the crystallite size of copper. Therefore, when the heat treatment time is t (minutes), a range of 0.1 <t <10 is appropriate, and a range of 220 ≧ T ≧ 70 is appropriate for the heat treatment temperature T (° C.). When the heat treatment temperature T is 70 ° C. or lower, the heat treatment effect cannot be obtained sufficiently. If the heat treatment temperature T is 220 ° C. or higher, it becomes difficult to control the crystallite size of copper, which affects copper oxidation, dimensional change of the plastic film, adhesion between the plastic film and the copper layer, and the like.

  In the present invention, the higher the temperature treatment, the longer the treatment may affect the dimensional change rate of the plastic film and the deterioration of flatness (vertical wrinkles and horizontal wrinkles). It is appropriate that the process is performed so that the relationship between (° C.) and t (minutes) satisfies the range of T> 95-25 Logt.

  Next, after the electrolytic copper plating in the present invention, before winding up, a method for producing a copper laminated type flexible printed circuit board material by an electrolytic copper plating method that is continuously put into a heat treatment process using an oven or a dryer Based on

  FIG. 1 shows a reel-to-reel system according to the present invention, which is a flexible printed circuit board material for continuously forming a copper layer on a metal vapor-deposited layer on a plastic film and continuously performing heat treatment using an oven. It is the whole schematic for demonstrating the process to manufacture.

  In FIG. 1, a long plastic film 2 having a metal vapor-deposited layer fed from an unwinding roller 1 is led to a plating bath 3 having a cathode 6 and an anode 5 to form a copper layer by electrolytic copper plating. Then, it is guided to the oven tub 4 separated by the side wall 7 and heat-treated. The heat-treated copper laminate type flexible printed circuit board material by the electrolytic copper plating method is wound up by the winding roller 7.

  The oven tank 4 may be one tank, but in the present invention, the oven tank 4 can be reciprocated a plurality of times as shown in FIG. 1, for example, preferably 5 to 10 reciprocations, more preferably 2 to 7 reciprocations. It can arrange | position and can heat-process continuously. By reciprocating the oven tank 4 a plurality of times, it is possible to lengthen the heat treatment time and save space for installing the oven.

  The flexible printed circuit board material of the present invention is suitably used for electronic devices such as circuit boards for liquid crystal display panels, bent circuit boards for mobile phones, hard disk suspensions as data recording devices, printer heads, and the like.

  Hereinafter, although the flexible printed circuit board material of this invention is demonstrated concretely by an Example, this invention is not limited at all by these Examples.

(1) Formation of a metal vapor deposition layer on a long plastic film substrate As an insulating film, a polyimide film “Kapton” (registered trademark) EN (manufactured by Toray DuPont, thickness 25 μm, width 520 mm, length 3000 m) Using. Vacuum plasma treatment is applied to one side of the polyimide film as a pretreatment, and then a nickel / chromium layer with a thickness of 5 nm and a copper layer with a thickness of 150 nm are formed by sputtering, and a long layer with a metal vapor deposition layer (conductive layer) A plastic film substrate was prepared. Furthermore, the back surface of the long plastic film base material with the metal vapor deposition layer (conductive layer) was similarly subjected to vacuum plasma treatment and sputtering to prepare a long plastic film base material with conductive layers on both sides.

(2) Evaluation of folding resistance A flexible printed circuit board material having a copper layer formed on one side is cut within 50 minutes in the longitudinal direction (longitudinal direction) and 10 mm in the lateral direction (lateral direction) within 5 minutes after the formation of the copper layer. A 0.3 mm thick gauge is placed on the flexible printed circuit board material on which the copper layer cut to the size is formed, one end is fixed, and the thickness of the thickness gauge is alternately bent with a force of 0.5 N as a copper layer. The number of breaks of the copper layer of the flexible printed circuit board material on which the film was formed was defined as a folding resistance index A. Here, the evaluation was made within 5 minutes after the formation of the copper layer, but it can be similarly evaluated within 240 hours after the formation of the copper layer.

  In addition, a flexible printed circuit board material in which a copper layer was formed on both sides was cut to 50 mm in the longitudinal direction (longitudinal direction) and 10 mm in the lateral direction (lateral direction) within 5 minutes after the copper layer was formed, and cut to the size. A flexible printed circuit board in which a copper layer is formed by placing a 0.3 mm thickness gauge on a flexible printed circuit board material on which a copper layer is formed, fixing one end, and bending the thickness gauge alternately with the thickness gauge as a fulcrum with a force of 0.5 N The number of times that either one of the copper layers of the material was first broken was defined as the folding resistance index B. Here, the evaluation was made within 5 minutes after the formation of the copper layer, but it can be similarly evaluated within 240 hours after the formation of the copper layer.

(3) Crystallite size of copper X-ray diffraction (XRD: X-Ray Diffraction) The crystallite size of 200 planes was measured using an apparatus. Note that JDX-3500 manufactured by JEOL Ltd. was used as the XRD apparatus. The XRD measurement conditions were 40 kV, 20 mA, a scan rate of 0.5 ° / min, a scan step of 0.02 °, and a measurement range of 2θ from 43 ° to 95 °.

Example 1
FIG. 1 shows a layer thickness of 4 μm on the metal deposition layer of a 25 μm-thick polyimide film “Kapton EN” (registered trademark, manufactured by Toray DuPont Co., Ltd.) having a metal deposition layer formed on one side by sputtering. Using the electrolytic copper plating apparatus shown, electrolytic copper plating was performed to form a copper layer. Next, the flexible printed circuit board material (diameter 7.6 cm) on which the wound and wound copper layer was formed was used at 80 ° C. for 12 hours using an oven (Espec Corp.) within 1 hour (Example 1-1). ) And 200 ° C. for 2 hours (Example 1-2). After the heat treatment, the bending resistance index A was measured. Moreover, the crystallite size (200 plane) of copper was measured using the XRD apparatus. The results are shown in Table 1.

(Example 2)
A flexible printed circuit board material having a copper layer formed thereon is wound up in the same manner as in Example 1 except that the copper layer is formed on both sides so that the copper layer thickness is 4 μm. The printed circuit board material was heat-treated within 1 hour at 80 ° C. for 12 hours (Example 2-1) and 200 ° C. for 2 hours (Example 2-2). Immediately after the heat treatment, the folding resistance index B was measured. Moreover, the crystallite size (200 plane) of copper was measured using the XRD apparatus. The results are shown in Table 1.

(Example 3)
A flexible printed circuit board material having a copper layer formed by winding a copper layer formed in the same manner as in Example 1 except that the thickness of the copper layer is 8 μm on one side. Was subjected to heat treatment at 80 ° C. for 12 hours (Example 3-1) and 200 ° C. for 2 hours (Example 3-2) within 1 hour, and the bending resistance index A was measured immediately after the heat treatment. Moreover, the crystallite size (200 plane) of copper was measured using the XRD apparatus. The results are shown in Table 1.

Example 4
A flexible printed circuit board material having a copper layer formed by winding a copper layer formed in the same manner as in Example 2 except that the thickness of the copper layer is 8 μm on both sides. Was subjected to heat treatment at 80 ° C. for 12 hours (Example 4-1) and 200 ° C. for 2 hours (Example 4-2) within 1 hour, and the bending resistance index B was measured immediately after the heat treatment. Moreover, the crystallite size (200 plane) of copper was measured using the XRD apparatus. The results are shown in Table 1.

(Example 5)
A 25 μm thick polyimide film “Kapton EN” (registered trademark, manufactured by Toray DuPont Co., Ltd.) with a metal vapor deposition layer having a thickness of 0.1 μm provided on one side by a sputtering method has a layer thickness on the metal vapor deposition layer of the 1500 m roll. The copper layer was formed by performing electrolytic copper plating using the electrolytic copper plating apparatus shown in FIG. Next, before winding up the flexible printed circuit board material on which the copper layer is formed, the flexible printed circuit board material on which the copper layer is formed is 210 ° C./0.2 minutes (Example 5-1), 200 ° C./minute (implemented) Example 5-2), 180 ° C for 2 minutes (Example 5-3), 150 ° C for 5 minutes (Example 5-4), 120 ° C for 8 minutes (Example 5-5), and 100 ° C for 9 minutes Heat treatment was performed in (Example 5-6). Immediately after the heat treatment, the folding resistance index A was measured. Moreover, the crystallite size (200 plane) of copper was measured using the XRD apparatus. The results are shown in Table 1.

(Example 6)
Except that the copper layer thickness is 4 μm on both sides, the flexible printed circuit board material formed with the copper layer is wound before winding the flexible printed circuit board material formed with the copper layer in the same manner as in Example 5. C./0.2 minutes (Example 6-1), 200.degree. C./minute (Example 6-2), 180.degree. C./2 minutes (Example 6-3), 150.degree. C./5 minutes (Example 6) 4), 120 ° C for 8 minutes (Example 6-5), 100 ° C for 9 minutes (Example 6-6), 190 ° C for 1 minute (Example 6-7), 140 ° C for 2 minutes (Example 6) −8) and 120 ° C. for 3 minutes (Example 6-9). Immediately after the heat treatment, the folding resistance index B was measured. Moreover, the crystallite size (200 plane) of copper was measured using the XRD apparatus. The results are shown in Table 1.

(Comparative Example 1)
The electrolytic copper plating shown in FIG. 1 is formed on the metal vapor-deposited layer of a 25 μm-thick polyimide film “Kapton EN” (registered trademark) having a metal vapor-deposited layer formed by sputtering on one side so that the layer thickness is 4 μm. Electrolytic copper plating was performed using an apparatus to form a copper layer. Next, the flexible printed circuit board material on which the copper layer was formed was wound, and the flexible printed circuit board material on which the wound copper layer was formed was not heat-treated (Comparative Example 1-1), and the oven (ESPEC within 1 hour). The heat treatment was performed at 80 ° C. for 0.2 hours (Comparative Example 1-2). No heat treatment was performed or heat treatment was performed, and the bending resistance index A was measured. Moreover, the crystallite size (200 plane) of copper was measured using the XRD apparatus. The results are shown in Table 2.

(Comparative Example 2)
The flexible printed circuit board material is formed by winding up the wound copper layer by winding the copper layer material in the same manner as in Comparative Example 1 except that the copper layer thickness is 4 μm on both sides. No heat treatment was performed (Comparative Example 2-1), and heat treatment was performed at 80 ° C. for 0.2 hours (Comparative Example 2-2) using an oven within 1 hour. No heat treatment was performed or heat treatment was performed, and the bending resistance index B was measured. Moreover, the crystallite size (200 plane) of copper was measured using the XRD apparatus. The results are shown in Table 2.

(Comparative Example 3)
A flexible printed circuit board material having a copper layer formed by winding a copper layer formed in the same manner as in Comparative Example 1 except that the thickness of the copper layer is 8 μm on one side. No heat treatment was performed (Comparative Example 3-1), and heat treatment was performed at 80 ° C. for 0.2 hour (Comparative Example 3-2) using an oven within 1 hour. No heat treatment was performed or heat treatment was performed, and the bending resistance index A and the crystallite size (200 planes) of copper were evaluated. The results are shown in Table 2.

(Comparative Example 4)
A flexible printed circuit board material having a copper layer formed by winding a copper layer formed in the same manner as in Comparative Example 2 except that the thickness of the copper layer is 8 μm on both sides. No heat treatment was performed (Comparative Example 4-1), and heat treatment was performed at 80 ° C. for 0.2 hour (Comparative Example 4-2) using an oven within 1 hour. No heat treatment was performed or heat treatment was performed, and the bending resistance index B and the crystallite size (200 planes) of copper were evaluated. The results are shown in Table 2.

(Comparative Example 5)
The electrolytic copper plating shown in FIG. 1 is formed on the metal vapor-deposited layer of a 25 μm-thick polyimide film “Kapton EN” (registered trademark) having a metal vapor-deposited layer formed by sputtering on one side so that the layer thickness is 4 μm. Electrolytic copper plating was performed using an apparatus to form a copper layer. Next, before winding the flexible printed circuit board material on which the copper layer was formed, heat treatment was not performed on the flexible printed circuit board material on which the copper layer was formed (Comparative Example 5-1), 100 ° C./0.2 minutes (Comparative Example) 5-2), 90 ° C. for 1 minute (Comparative Example 5-3), 85 ° C. for 2 minutes (Comparative Example 5-4), 75 ° C. for 5 minutes (Comparative Example 5-5), and 68 ° C. for 10 minutes. Heat treatment was performed in (Comparative Example 5-6). No heat treatment was performed or heat treatment was performed, and the bending resistance index A and the crystallite size (200 planes) of copper were evaluated. The results are shown in Table 2.

(Comparative Example 6)
Heat treatment of the flexible printed circuit board material formed with the copper layer before winding the flexible printed circuit board material formed with the copper layer in the same manner as in Example 5 except that the copper layer thickness is 4 μm on both sides. (Comparative Example 6-1), 100 ° C. · 0.2 minutes (Comparative Example 6-2), 90 ° C. · 1 minute (Comparative Example 6-3), 85 ° C. · 2 minutes (Comparative Example 6-4) ), 75 ° C. for 5 minutes (Comparative Example 6-5), and 68 ° C. for 10 minutes (Comparative Example 6-6). For the samples that were not heat-treated or heat-treated, the folding resistance index B and the copper crystallite size (200 planes) were evaluated. The results are shown in Table 2.

  Table 1 (Examples) and Table 2 (Comparative Examples) show the evaluation results of the above folding resistance index A, folding resistance index B, and copper crystallite size. The folding resistance index in the table represents the number of times, and the crystallite size of copper represents angstrom. Anything within the scope of the present invention showed good results.

  FIG. 2 is a graph showing the results of Examples 5 and 6 and Comparative Examples 5 and 6 of the present invention as Logt on the X axis and temperature T on the Y axis. From FIG. 2, it can be seen that the folding resistance index A and the folding resistance index B within the range of the present invention can be obtained by satisfying T> 95-25Logt.

FIG. 1 shows a reel-to-reel system according to the present invention, which is a flexible printed circuit board material for continuously forming a copper layer on a metal vapor-deposited layer on a plastic film and continuously performing heat treatment using an oven. It is the whole schematic diagram explaining the process to manufacture. FIG. 2 is a graph showing the results of Examples 5 and 6 and Comparative Examples 5 and 6 of the present invention with Logt on the X axis and temperature T on the Y axis.

Explanation of symbols

A: Unwinding roller B: Long plastic film having a copper layer C: Plating bath D: Oven bath E: Anode (anode)
F: Cathode
G: Side wall H: Winding roller 1: Examples 5-1 and 6-1
2: Examples 5-2 and 6-2
3: Examples 5-3 and 6-3
4: Examples 5-4 and 6-4
5: Examples 5-5 and 6-5
6: Examples 5-6 and 6-6
7: Example 6-7
8: Example 6-8
9: Example 6-9
10: Comparative examples 5-2 and 6-2
11: Comparative examples 5-3 and 6-3
12: Comparative examples 5-4 and 6-4
13: Comparative examples 5-5 and 6-5
14: Comparative examples 5-6 and 6-6

Claims (11)

  A flexible printed circuit board material obtained by laminating a copper layer having a thickness of 4 μm or more and 12 μm or less on one surface of a plastic film by electrolytic copper plating, and within 240 hours after electrolytic copper plating of the copper layer A flexible printed circuit board material having a folding index A of 300 times or more.   A material for a flexible printed circuit board, in which a copper layer having a thickness of 4 μm or more and 12 μm or less is laminated on both surfaces of a plastic film by electrolytic copper plating, and the folding index B within 240 hours after electrolytic copper plating of the copper layer Is a flexible printed circuit board material characterized by 30 times or more.   3. The flexible printed circuit board material according to claim 1, wherein the copper crystallite size (200 planes) of the copper layer within 240 hours after the electrolytic copper plating is 200 angstroms or more. The flexible printed circuit board material according to claim 1, wherein the plastic film is a polyimide film.   The material for a flexible printed circuit board according to any one of claims 1 to 3, wherein the plastic film is a polyethylene terephthalate film.   The flexible printed circuit board material according to claim 1, wherein the plastic film has a thickness of 12 to 40 μm.   7. A flexible printed circuit board according to claim 1, wherein a nickel / chromium alloy layer is formed on a plastic film, and then a copper layer is laminated thereon by an electrolytic copper plating method. material.   In the method for producing a copper laminate type flexible printed circuit board material by electrolytic copper plating, after winding electrolytic copper on a plastic film, the wound material is heat-treated at a temperature of 60 to 200 ° C. for 1 to 15 hours within 120 hours. The manufacturing method of the material for flexible printed circuit boards in any one of Claims 1-7 characterized by these.   In the method for producing a copper laminate type flexible printed circuit board material by electrolytic copper plating, after winding electrolytic copper on a plastic film, the wound material is heat-treated at a temperature of 60 to 200 ° C. for 1 to 15 hours within 120 hours. A method for producing a material for a flexible printed circuit board.   In the method for producing a copper laminated type flexible printed circuit board material by electrolytic copper plating, the heat treatment temperature T (° C.) is 220 ≧ and the heat treatment time t (minutes) is before winding the plastic film after electrolytic copper plating. Heat treatment is performed under a temperature condition in which 0.1 <t <10 and the relationship between the heat treatment temperature T and the heat treatment time t satisfies a range of T> 95-250 Logt. A method for producing a material for a flexible printed circuit board according to claim 1.   In the method for producing a copper laminate type flexible printed circuit board material by electrolytic copper plating, the heat treatment temperature T (° C.) is 220 ≧ T and the heat treatment time t (minute) before winding the plastic film after electrolytic copper plating. Is 0.1 <t <10, and the heat-treatment temperature T and the heat treatment time t satisfy the range of T> 95-250Logt. Manufacturing method.

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