JP6373166B2 - Surface-treated copper foil and laminate - Google Patents

Description

  The present invention relates to a surface-treated copper foil and a laminate formed using the surface-treated copper foil.

  Conventionally, a flexible printed wiring board (FPC) or the like has been used as a wiring board of an electronic device such as a mobile phone. FPC is formed with the laminated board provided with copper foil and a resin base material, for example. A copper wiring (circuit pattern) is formed on the laminate by removing the copper foil at a predetermined location by etching or the like. The laminated board is required to have high adhesion between the copper foil and the resin substrate (hereinafter also simply referred to as “adhesion”), and the copper wiring is difficult to peel off from the resin substrate. Therefore, as the copper foil, for example, a surface-treated copper foil having an anchor effect and improved adhesion by providing a roughened copper plating layer containing plating particles on any main surface of the copper foil base material is used. Has been proposed (see, for example, Patent Documents 1 to 3).

JP 2004-238647 A JP 2006-155899 A JP 2010-218905 A

  However, if the particle diameter of the plating particles is increased and the surface of the surface-treated copper foil is roughened in order to increase the above-mentioned adhesion, the transparency of the resin base material at the location where the copper foil has been removed is reduced. There is. Therefore, when mounting an electronic component or the like on the laminate, it may be difficult to recognize the alignment mark or the like over the resin base material where the copper foil has been removed, and it may be difficult to position the mounting position of the electronic component or the like. .

  The present invention solves the above problems and maintains the adhesion between the surface-treated copper foil and the resin base material when the laminated board is formed, and the resin base after the surface-treated copper foil is removed from the laminated board. The object is to provide a technology that ensures the transparency of the material.

According to one aspect of the invention,
A copper foil base material;
A roughened copper plating layer that is provided on at least one main surface of the copper foil base material and includes a plurality of plating particles grown in a predetermined growth direction, and
The average value of the particle diameter along the principal surface of the copper foil base material of the plating particles is 0.05 μm or more and 0.8 μm or less,
The average value of the particle diameter along the growth direction of the plating particles is 0.05 μm or more and 1.2 μm or less,
Provided is a surface-treated copper foil in which an angle formed by the growth direction of the plating particles and the main surface of the copper foil base is 20 ° or more and 90 ° or less.

According to another aspect of the invention,
A surface-treated copper foil provided with a roughened copper plating layer that is provided on at least one main surface of the copper foil base material and the copper foil base material and includes a plurality of plating particles grown in a predetermined growth direction, and
A resin base material bonded to the surface-treated copper foil so as to face the roughened copper plating layer,
The average value of the particle diameter along the principal surface of the copper foil base material of the plating particles is 0.05 μm or more and 0.8 μm or less,
The average value of the particle diameter along the growth direction of the plating particles is 0.05 μm or more and 1.2 μm or less,
There is provided a laminated board in which an angle formed by the growth direction of the plating particles and the main surface of the copper foil base material is 20 ° or more and 90 ° or less.

  According to the present invention, the adhesiveness between the surface-treated copper foil and the resin base material when the laminated plate is formed can be maintained, and the transparency of the resin base material after the surface-treated copper foil is removed from the laminated plate can be maintained. It can be secured.

It is a schematic sectional drawing of a laminated board provided with the surface treatment copper foil concerning one Embodiment of this invention. (A)-(d) is an example of the longitudinal cross-sectional schematic diagram of the plating particle contained in the roughening copper plating layer with which the surface-treated copper foil concerning one Embodiment of this invention is provided, respectively. It is an example of the SEM image of the upper surface of the roughening copper plating layer with which the surface treatment copper foil concerning one Embodiment of this invention is provided.

  In recent years, with the demand for further downsizing and thinning of electronic devices, FPCs used in electronic devices are also required to be further downsized and thinned. Therefore, for example, it is considered to reduce the thickness of the FPC by reducing the thickness of the adhesive layer provided on the bonding surface of the resin base material to the copper foil. However, when the thickness of the adhesive layer is reduced, the adhesiveness between the surface-treated copper foil and the resin base material is lowered depending on the surface roughness of the surface of the surface-treated copper foil to be bonded to the resin base material. May end up. The present invention has been made to solve the specific problems that occur when the thickness of the adhesive layer is reduced.

(1) Structure of surface-treated copper foil and laminated board The structure of the laminated board and surface-treated copper foil concerning one Embodiment of this invention is demonstrated, referring FIGS. 1-3.

(Laminated board)
As shown in FIG. 1, a laminate (CCL: Copper Cladd Laminate) 10 according to the present embodiment includes a surface-treated copper foil 1 having a roughened copper plating layer 3 provided on at least one main surface, and a roughened copper foil 1. And a resin base material 11 provided so as to face the copper chloride plating layer 3. For example, the laminated board 10 is formed by bonding the surface-treated copper foil 1 to both main surfaces of the resin base material 11. Specifically, the laminate 10 has both the resin base material 11 so that the surface-treated copper foil 1 faces the resin base material 11 and the roughened copper plating layer 3 faces the resin base material 11. The surface-treated copper foil 1 is bonded to the main surface.

  As the resin base material 11, for example, a polyimide (PI) resin film, a polyester film such as polyethylene terephthalate (PET), a liquid crystal polymer (LCP), or the like is used. Moreover, it is preferable that the adhesive layer is provided in the bonding surface with the surface treatment copper foil 1 of the resin base material 11. FIG. As the adhesive layer, for example, a thermoplastic polyimide (TPI) layer can be formed.

(Surface treated copper foil)
The surface-treated copper foil 1 used for the above-described laminated plate 10 includes a copper foil base material 2. As the copper foil base material 2, for example, a rolled copper foil or an electrolytic copper foil can be used. As the copper foil base material 2, it is more preferable to use a rolled copper foil that is superior in bending resistance to the electrolytic copper foil and is not easily broken even if it is repeatedly bent. The thickness of the copper foil base material 2 is preferably 5 μm or more and 18 μm or less, for example.

  The copper foil base material 2 is made of pure copper such as oxygen-free copper (OFC: Oxygen-Free Copper) or tough pitch copper (TPC: Tow-Pitch Copper). Oxygen-free copper is a copper material having a purity specified in JIS C1020, JIS H3100, etc. of 99.96% or higher. The oxygen-free copper may contain, for example, about several ppm of oxygen. Tough pitch copper is, for example, a copper material having a purity of 99.9% or more as defined in JIS C1100, JIS H3100, or the like. The tough pitch copper may contain, for example, about 100 ppm to 600 ppm of oxygen. The copper foil base material 2 may be formed from a dilute copper alloy obtained by adding a predetermined additive such as a small amount of tin (Sn) or silver (Ag) to oxygen-free copper or tough pitch copper. Thereby, the heat resistance etc. of the copper foil base material 2 can be improved.

  A roughened copper plating layer 3 is provided on any main surface of the copper foil base 2. The roughened copper plating layer 3 is preferably in a state in which no roughening omission occurs. For example, it is preferable that the roughened copper plating layer 3 is formed so that the copper foil base material 2 is not exposed when the roughened copper plating layer 3 is viewed from above.

  The roughened copper plating layer 3 includes, for example, a plurality of plated particles (roughened) grown in a predetermined growth direction on any main surface of the copper foil base 2 as shown in FIGS. 3a) is included. The plated particles 3a are made of, for example, copper (Cu) (that is, Cu alone). The roughened copper plating layer 3 (plating particles 3a) suppresses excessive growth (abnormal growth) of Cu and plating particles 3a (prevents the generation of dendrites) and makes the size of the plating particles 3a uniform, for example. Preferably, it is formed using a plating solution containing metal ions. Specifically, iron (Fe), nickel (Ni), molybdenum (Mo), tungsten (W), cobalt (Co), zinc (Zn), chromium (Cr), etc. are used as such metal ions. . For example, iron sulfate heptahydrate or sodium molybdate (Mo acid Na) may be added to the plating solution for forming the roughened copper plating layer 3 (hereinafter also referred to as “roughened copper plating solution”). preferable. In addition, the roughening copper plating layer 3 may be formed using the above-mentioned plating solution which does not contain metal ions made of Cu, for example.

  It is preferable that the average value of the particle diameter W along the main surface of the copper foil base material 2 of the plating particle 3a is, for example, 0.05 μm or more and 0.8 μm or less. The particle diameter W along the main surface of the copper foil base material 2 of the plating particle 3a is, for example, the particle diameter along the main surface of the copper foil base material 2 of the plating particle 3a when the plating particle 3a is viewed from above. It is the maximum value. The average value of the particle diameter W along the main surface of the copper foil base material 2 of the plated particles 3a is, for example, the concentration of metal ions in the roughened copper plating solution (for example, the concentration of iron sulfate heptahydrate or Mo acid Na). Alternatively, it can be controlled by adjusting the temperature of the roughened copper plating solution. Hereinafter, the average value of the particle diameters of the plating particles 3a along the main surface of the copper foil base material 2 is also referred to as the horizontal average particle diameter of the plating particles 3a.

  Moreover, it is preferable that the average value of the particle diameter D along the growth direction of the plating particle 3a is, for example, 0.05 μm or more and 1.2 μm or less. The growth direction of the plating particle 3a is the main growth direction of the plating particle 3a. In the longitudinal sectional view of the plating particle 3a, a line (growth axis L) extending from the middle point O to the bottom T of the plating particle 3a. ) Direction. Further, the particle diameter D along the growth direction of the plating particle 3a is, for example, the length between the vertex T and the midpoint O of the bottom in the longitudinal sectional view of the plating particle 3a. That is, the particle diameter D along the growth direction of the plating particles 3a is, for example, the length of the growth axis L of the plating particles 3a. The average value of the particle diameter D along the growth direction of the plated particles 3a is controlled by adjusting, for example, the liquid temperature of the roughened copper plating solution or the plating time of the plating process for forming the roughened copper plated layer 3. Can do. In the following, the average value of the particle diameter D along the growth direction of the plating particles 3a is also referred to as the average particle diameter in the growth direction of the plating particles 3a.

  Furthermore, it is preferable that the angle θ formed by the growth direction (growth axis L) of the plated particles 3a and the main surface of the copper foil base 2 is, for example, 20 ° or more and 90 ° or less. For example, the average value of the angle θ formed by the growth direction of the plated particles 3a included in the roughened copper plating layer 3 and the main surface of the copper foil base 2 is preferably 20 ° or more and 90 ° or less, and 60 ° or more. More preferably, it is 90 ° or less. The maximum value of the angle θ formed by the growth direction of the plating particles 3a and the main surface of the copper foil base 2 is 90 °. In addition, the angle θ formed by the growth direction of the plating particles 3a and the main surface of the copper foil base 2 is an acute angle. For example, the growth direction of the plating particle 3a and the copper foil base material 2 are both the case where the angle θ formed by the growth direction of the plating particle 3a and the main surface of the copper foil base material 2 is 135 ° and 45 °. The angle θ made with the principal surface of the film is 45 °. The angle θ formed by the growth direction of the plated particles 3a and the main surface of the copper foil base 2 can be controlled by adjusting the current density of the plating process for forming the roughened copper plating layer 3, for example. Hereinafter, the angle θ formed by the growth direction of the plating particles 3a and the main surface of the copper foil base 2 is also referred to as the growth angle θ of the plating particles 3a.

  When at least one of the average particle diameter in the horizontal direction of the plating particles 3a or the average particle diameter in the growth direction of the plating particles 3a is less than 0.05 μm, or the growth angle θ of the plating particles 3a is less than 20 °, In the laminated board 10, the surface treatment copper foil 1 which contacts the resin base material 11 has a surface area too small, and an anchor effect may be insufficient. Therefore, desired adhesion may not be maintained. In addition, adhesiveness is the adhesiveness of the surface-treated copper foil 1 and the resin base material 11 in the laminated board 10. FIG.

  In the laminate 10, the average particle diameter in the horizontal direction of the plating particles 3 a and the average particle diameter in the growth direction of the plating particles 3 a are each 0.05 μm or more, and the growth angle θ of the plating particles 3 a is 20 ° or more. The surface area of the surface-treated copper foil 1 in contact with the resin base material 11 can be sufficiently increased. As a result, the anchor effect can be sufficiently obtained. Thereby, desired adhesiveness can be maintained. For example, the peel strength when the surface-treated copper foil 1 is peeled off from the resin substrate 11 after the surface-treated copper foil 1 is bonded to the resin substrate 11 (hereinafter also simply referred to as “peel strength”) is 0.7 N. / Mm or more. By setting the growth angle θ of the plated particles 3a to 60 ° or more, the surface area of the surface-treated copper foil 1 in contact with the resin substrate 11 in the laminated plate 10 can be further increased.

  However, if the average particle diameter in the horizontal direction of the plating particles 3a exceeds 0.8 μm or the average particle diameter in the growth direction of the plating particles 3a exceeds 1.2 μm, the transparency may be lowered. In addition, transparency refers to both main surfaces of the resin base material 11 so that the surface-treated copper foil 1 faces the resin base material 11 and the roughened copper plating layer 3 faces the resin base material 11. After the surface-treated copper foil 1 was bonded to the resin base material 11, the surface-treated copper foil 1 was removed from both main surfaces of the resin base material 11 (hereinafter also referred to as “resin base material 11 after removing the copper foil”). .) Transparency. Here, the fact that the average particle diameter in the horizontal direction and the growth direction of the plating particles 3a is increased substantially means that the respective sizes of the plating particles 3a included in the roughened copper plating layer 3 are increased. doing. When the average particle diameter in the horizontal direction or the growth direction of the plating particles 3a is increased, the surface-treated copper foil 1 is roughened when the surface-treated copper foil 1 and the resin base material 11 are bonded to form the laminated plate 10. Plural portions formed (transferred) to the resin base material 11 by pressing the convex portions formed of the plating particles 3 a against the surface (roughened surface) on which the copper plating layer 3 is provided are pressed against the resin base material 11. The size of each recess is too large. As a result, the transparency of the resin base material 11 after removing the copper foil may decrease.

  Moreover, when the average particle diameter of the growth direction of the plating particle 3a exceeded 1.2 micrometers, the resin base material 11 and the surface treatment copper foil 1 were bonded together through the adhesive bond layer provided in the resin base material 11. At this time, the convex portion formed by the plated particles 3 a may penetrate (break through) the adhesive layer on the roughened surface of the surface-treated copper foil 1. As a result, in the resin base material 11 after removing the copper foil, part of the surface-treated copper foil 1 may remain on the surface of the resin base material 11. That is, so-called root residue (etching residue) may occur.

  By setting the average particle diameter in the horizontal direction of the plated particles 3a to 0.8 μm or less and the average particle diameter in the growth direction of the plated particles 3a to 1.2 μm or less, desired transparency can be ensured. For example, the HAZE value of the resin base material 11 after removing the copper foil can be 80% or less. The HAZE value is also referred to as turbidity or haze, and the greater the HAZE value, the lower the transparency. Moreover, in the resin base material 11 after copper foil removal, it can suppress that a part of surface-treated copper foil 1 remains on the surface of the resin base material 11. FIG.

  Here, the calculation method of the average particle diameter of the horizontal direction of the plating particle 3a is demonstrated. For example, by the SEM method, the roughened copper plated layer is formed from directly above the roughened copper plated layer 3 (in a direction perpendicular to the main surface of the roughened copper plated layer 3) at a predetermined observation magnification (for example, 30000 times). 3 (the roughened surface of the surface-treated copper foil 1) is observed (photographed). Thereby, for example, an SEM image of the upper surface of the roughened copper plating layer 3 as shown in FIG. 3 is obtained. A predetermined number (for example, 10) of plating particles 3a is arbitrarily extracted from the plating particles 3a observed in the obtained SEM image, and the particle diameter (maximum diameter) of the extracted plating particles 3a is measured. Is the particle diameter W along the copper foil substrate 2 of the plated particles 3a. And the average value of the particle diameter W along the copper foil base material 2 of the measured plating particle 3a is computed, and let this be the average particle diameter of the horizontal direction of the plating particle 3a. For example, as shown in FIG. 2 (d), a plurality of plating particles 3a overlap in the height direction of the roughened copper plating layer 3 (that is, other plating particles 3a grow on one plating particle 3a). The particle diameter W along the principal surface of the copper foil base material 2 of the plated particle 3a located at the uppermost stage is measured.

  Next, a method for calculating the average particle diameter in the growth direction of the plated particles 3a will be described. For example, a predetermined number (for example, 30) of plated particles 3a is arbitrarily selected from an SEM image obtained by observing the longitudinal section of the roughened copper plating layer 3 at a predetermined observation magnification (for example, 10,000 times) by the SEM method. To extract. For each of the extracted plated particles 3a, the vertex T and the middle point O of the bottom are detected, the distance between the vertex T and the middle point O of the bottom is measured, and this is measured in the growth direction of the plated particles 3a. It is assumed that the particle diameter D is along. And the average value of the particle diameter D along the growth direction of the obtained plating particle 3a is calculated, and let this be the average particle diameter of the growth direction of the plating particle 3a. In addition, when the several plating particle 3a has overlapped in the height direction of the roughening copper plating layer 3, the particle diameter D along the growth direction of the plating particle 3a located in the uppermost stage is measured.

  Moreover, the measuring method of angle (theta) which the growth direction of the plating particle 3a and the main surface of the copper foil base material 2 make is demonstrated. For example, from a SEM image obtained by observing the longitudinal section of the roughened copper plating layer 3 at a predetermined observation magnification (for example, 10,000 times) by the SEM method, a predetermined number (for example, 30) of plated particles 3a is arbitrarily selected. Extract. For each of the extracted plated particles 3a, the vertex T and the middle point O of the bottom are detected, and the direction from the middle point O of the bottom toward the vertex T is defined as the growth direction of the plated particles 3a. And about each extracted plating particle 3a, angle (theta) which the growth direction of the plating particle 3a and the main surface of the copper foil base material 2 make is measured. Moreover, you may calculate an average value using angle (theta) which the growth direction of the obtained plating particle 3a and the main surface of the copper foil base material 2 make. For example, as shown in FIG. 2 (d), when a plurality of plating particles 3 a overlap in the height direction of the roughened copper plating layer 3, the middle point O of the bottom of the plating particles 3 a located at the lowest level The direction toward the apex T of the plating particle 3a located at the uppermost stage is defined as the growth direction of the plating particle 3a.

  Moreover, it is preferable that the thickness of the roughening copper plating layer 3 is 0.03 micrometer or more and 1.1 micrometers or less, for example. In addition, the thickness of the roughened copper plating layer 3 is a thickness when the unevenness of the roughened copper plating layer 3 is averaged (that is, an average thickness).

  When the thickness of the roughened copper plating layer 3 is less than 0.03 μm, the size of each plating particle 3 a included in the roughened copper plating layer 3 may be too small. For example, the average particle diameter in the horizontal direction of the plating particles 3a and the average particle diameter in the growth direction of the plating particles 3a may be less than 0.05 μm. Further, since the amount of plating for forming the roughened copper plating layer 3 is reduced, the growth angle θ of each plating particle 3a may be, for example, less than 20 °. As a result, in the laminated board 10, the surface treatment copper foil 1 which contacts the resin base material 11 is too small in surface area, and a sufficient anchor effect may not be obtained. Therefore, desired adhesion may not be maintained.

  By making the thickness of the roughened copper plating layer 3 0.03 μm or more, the average particle diameter in the horizontal direction of the plating particles 3 a and the average particle diameter in the growth direction of the plating particles 3 a are each more reliably 0.05 μm or more. Can be. Further, the growth angle θ of the plated particles 3a can be made sufficiently large (for example, 20 ° or more). As a result, an anchor effect can be obtained more and desired adhesion can be more reliably maintained. For example, the peel strength can be more reliably maintained at 0.7 N / mm or more.

  However, when the thickness of the roughened copper plating layer 3 exceeds 1.1 μm, the average particle diameter in the horizontal direction of the plating particles 3 a exceeds 0.8 μm, or the average particle diameter in the growth direction of the plating particles 3 a is 1. The size of each plated particle 3a may be larger than 2 μm. As a result, desired transparency may not be ensured. Further, when the surface-treated copper foil 1 and the resin base material 11 are bonded together, the convex portion formed on the roughened surface of the surface-treated copper foil 1 penetrates the adhesive layer provided on the resin base material 11. There is. Therefore, in the resin base material 11 after removing the copper foil, a part of the surface-treated copper foil 1 may remain on the surface of the resin base material 11.

  By setting the thickness of the roughened copper plating layer 3 to 1.1 μm or less, the average particle diameter in the horizontal direction of the plating particles 3 a is set to 0.8 μm or less, and the average particle diameter in the growth direction of the plating particles 3 a is 1.2 μm. The following can be made more reliable. As a result, desired transparency can be ensured more reliably. For example, the HAZE value of the resin base material 11 after removing the copper foil can be more reliably set to 80% or less. Moreover, in the resin base material 11 after copper foil removal, it can suppress that a part of surface-treated copper foil 1 remains on the surface of the resin base material 11. FIG.

  Between the copper foil base material 2 and the roughened copper plating layer 3, a base plating layer 4 that functions as a base layer of the roughened copper plating layer 3 may be provided. The base plating layer 4 is a plating layer having a flat surface, for example. For example, the base plating layer 4 is preferably formed of a copper plating layer. In order to prevent the plating time for forming the base plating layer 4 from increasing and the productivity of the surface-treated copper foil 1 from decreasing, the thickness of the base plating layer 4 is, for example, 0.1 μm or more and 0.5 μm or less. It is preferable that

  In order to improve the heat resistance and chemical resistance of the surface-treated copper foil 1, it is preferable that the rust prevention layer 5 is provided so as to cover at least the upper surface of the roughened copper plating layer 3. The thickness of the rust preventive layer 5 is preferably 6 nm or more and 35 nm or less, for example. When the thickness of the rust preventive layer 5 is less than 6 nm, the heat resistance and chemical resistance of the surface-treated copper foil 1 may be insufficient. By setting the thickness of the rust prevention layer 5 to 6 nm or more, the heat resistance and chemical resistance of the surface-treated copper foil 1 can be sufficiently improved. However, since the rust preventive layer 5 is difficult to be etched, when the thickness of the rust preventive layer 5 exceeds 35 nm, a part of the surface-treated copper foil 1 of the resin base 11 is removed from the resin base 11 after the copper foil is removed. It may remain on the surface.

  As the rust prevention layer 5, for example, in order from the copper foil base material 2 side, a Ni plating layer (or a Ni alloy plating layer such as an alloy plating layer of Ni and Co) and a Zn plating layer (or a Zn alloy plating layer) And a chromate treatment layer (trivalent chromium chemical conversion treatment layer) and a silane coupling layer as a chemical conversion treatment film are preferably provided.

  It is preferable that the thickness of the Ni plating layer is, for example, 4 nm or more and 20 nm or less, whereby the Cu in the surface-treated copper foil 1 can be prevented from diffusing to the resin base material 11 side. The thickness of the Zn plating layer is preferably, for example, 1 nm or more and 10 nm or less, whereby the heat resistance of the surface-treated copper foil 1 can be further improved. The thickness of the chromate treatment layer is preferably 1 nm or more and 5 nm or less, for example. Further, the thickness of the silane coupling layer may be very thin, which can further improve the adhesion.

(2) Manufacturing method of surface-treated copper foil Next, one Embodiment of the manufacturing method of the surface-treated copper foil 1 and the laminated board 10 concerning this embodiment is described.

[Surface treatment copper foil formation process]
First, the surface-treated copper foil 1 according to the present embodiment is formed.

(Copper foil base material formation process)
As the copper foil base material 2, for example, a rolled copper foil or an electrolytic copper foil is formed. For example, when forming a rolled copper foil as the copper foil base material 2, first, a pure copper ingot made of oxygen-free copper or tough pitch copper, oxygen-free copper or tough pitch copper as a parent phase, and a predetermined amount in the mother phase An ingot of a dilute copper alloy to which additives such as Sn and Ag are added is cast. And a predetermined hot rolling process, a predetermined cold rolling process, a predetermined annealing process, etc. are performed with respect to the cast ingot, and the rolled copper foil of predetermined thickness (for example, 5 micrometers or more and 18 micrometers or less) is formed.

(Under plating layer forming process)
When the copper foil base material forming step is completed, a base plating layer 4 having a predetermined thickness (for example, 0.1 μm or more and 0.5 μm or less) is formed on at least one main surface of the copper foil base material 2. Specifically, in the plating solution for forming the base plating layer 4 (base plating solution), for example, electrolytic plating is performed at a current density lower than the limit current density of the base plating solution to form the base plating layer 4. As the base plating solution, for example, an acidic copper plating bath mainly containing copper sulfate and sulfuric acid can be used. If the current density is set to be equal to or higher than the limit current density, the unevenness of the surface of the base plating layer 4 becomes large, and the base plating layer 4 having a flat surface may not be formed.

  The electrolysis conditions such as the liquid composition, liquid temperature, and current density of the base plating solution can be set within the range shown in Table 1 below, for example. At this time, it is preferable to use a Cu plate as the anode and to use the copper foil base material 2 itself, which is an object to be plated, as the cathode.

  In order to further improve the productivity of the surface-treated copper foil 1, the current density is preferably as high as possible within the range shown in Table 1.

(Roughening copper plating layer forming process)
When the base plating layer forming step is finished, a predetermined thickness (for example, 0.04 μm or more and 1.1 μm or less) is formed on the base plating layer 4 by, for example, roll-to-roll type continuous electrolytic (electric) plating treatment. ) Of the roughened copper plating layer 3 is formed. Specifically, in the plating solution (roughened copper plating solution) for forming the roughened copper plating layer 3, for example, a current density equal to or higher than the limit current density of the roughened copper plating solution (so-called “bake plating”). An electrolytic plating process (roughening process) is performed at a current density) to form a roughened copper plating layer 3. For example, an acidic copper plating bath mainly composed of copper sulfate or sulfuric acid can be used as the roughened copper plating solution. Further, it is preferable to add a predetermined amount of iron sulfate heptahydrate, Mo acid Na or the like to the roughened copper plating solution.

  The electrolytic conditions such as the liquid composition, liquid temperature, and current density of the roughened copper plating solution can be set within the range shown in Table 2 below, for example. At this time, it is preferable to use a Cu plate as the anode and to use the copper foil base material 2 itself, which is a target to be roughened, as the cathode.

  In addition, as the concentration of iron sulfate heptahydrate (metal ion that makes the size of the plating particles 3a uniform) in the roughened copper plating solution increases and the liquid temperature of the roughened copper plating solution increases, for example, plating The horizontal average particle diameter of the particles 3a tends to increase. In addition, the longer the plating time for the roughening treatment and the higher the temperature of the roughened copper plating solution, the larger the average particle diameter in the growth direction of the plated particles 3a, for example. For example, when the charge amount is the same (= current density × plating time), for example, the higher the current density, the larger the growth angle θ of the plated particles 3a tends to be (closer to 90 °). Accordingly, the roughened copper plating solution so that the average particle diameter in the horizontal direction of the plating particles 3a, the average particle diameter in the growth direction of the plating particles 3a, and the growth angle θ of the plating particles 3a are in desired ranges, respectively. It is preferable to adjust appropriately the density | concentration of the metal ion which makes the magnitude | size of the inside plating particle 3a uniform, the liquid temperature of a roughening copper plating solution, plating time, a current density, etc.

(Rust prevention layer formation process)
When the roughened copper plating layer forming step is completed, a rust prevention layer 5 having a predetermined thickness (for example, 6 nm or more and 35 nm or less) is formed on the roughened copper plating layer 3. For example, as the rust preventive layer 5, a Ni plating layer (or Ni alloy plating layer) having a predetermined thickness (for example, 4 nm or more and 20 nm or less) and a predetermined thickness (for example, 1 nm or more and 10 nm or more) in order from the roughened copper plating layer 3 side. Below) Zn plating layer (or Zn alloy plating layer), a trivalent chromium chemical conversion treatment layer having a predetermined thickness (for example, 1 nm or more and 5 nm or less), and a silane coupling layer. The trivalent chromium chemical conversion treatment layer is preferably formed using, for example, a trivalent chromium type reactive chromate solution.

[Laminated plate forming process]
When the rust preventive layer forming step is finished and the surface-treated copper foil forming step is finished, the surface-treated copper foil 1 and the resin base material 11 are bonded together to form the laminate 10. Specifically, the surface-treated copper foil 1 is placed on the resin substrate 11 so that the surface-treated copper foil 1 faces the resin substrate 11 and the roughened copper plating layer 3 faces the resin substrate 11. It arrange | positions on both main surfaces, the surface-treated copper foil 1 and the resin base material 11 are bonded together, and the laminated board 10 is formed. Bonding of the surface-treated copper foil 1 and the resin base material 11 is performed by heating the surface-treated copper foil 1 and the resin base material 11 to a predetermined temperature (for example, 150 ° C. or higher and 350 ° C. or lower) using, for example, a vacuum press. On the other hand, a predetermined pressure (for example, 20 MPa or less) can be applied to the surface-treated copper foil 1 and the resin base material 11 for a predetermined time (for example, 1 minute to 120 minutes).

(3) Effects According to the Present Embodiment According to the present embodiment, one or a plurality of effects described below are exhibited.

(A) The average value of the particle diameter along the main surface of the copper foil base material 2 of the plurality of plating particles 3a contained in the roughened copper plating layer 3, the average value of the particle diameter along the growth direction of the plating particles 3a, In addition, by making the angle θ formed between the growth direction of the plated particles 3a and the main surface of the copper foil base material 2 within a desired range, it is possible to ensure desired transparency while maintaining desired adhesion. . Specifically, the average particle diameter in the horizontal direction of the plating particles 3a is set to 0.05 μm or more and 0.8 μm or less, the average particle diameter in the growth direction of the plating particles 3a is set to 0.05 μm or more and 1.2 μm or less, and the plating particles 3a By making the growth angle θ of 20 ° or more and 90 ° or less, the HAZE value of the resin base material 11 after removing the copper foil can be made 80% or less while maintaining the peel strength at 0.7 N / mm or more.

  By forming the peel strength to 0.7 N / mm or more, for example, in the FPC formed with the laminated plate 10 using the surface-treated copper foil 1, a predetermined portion of the surface-treated copper foil 1 is removed by etching or the like. It can suppress that copper wiring peels from the resin base material 11. FIG. Accordingly, it is possible to suppress a decrease in the reliability of the FPC.

  Further, by setting the HAZE value of the resin base material 11 after removing the copper foil to 80% or less, for example, when mounting an electronic component or the like on the FPC formed by the laminated plate 10 using the surface-treated copper foil 1, With a CCD camera or the like, it is possible to easily recognize the copper wiring, the positioning mark, and the like through the resin base material 11 at the place where the surface-treated copper foil 1 is removed. As a result, it is possible to improve the mounting workability when mounting electronic components or the like on the FPC, for example.

(B) When the laminate 10 is formed using the surface-treated copper foil 1 by setting the average particle diameter in the growth direction of the plated particles 3 a to 0.05 μm or more and 1.2 μm or less, the surface-treated copper foil 1 It can suppress that the convex part formed of the plating particle 3a on the roughened surface penetrates the adhesive layer provided on the resin substrate 11. Thereby, in the resin base material 11 after copper foil removal, it can suppress that a part of surface-treated copper foil 1 remains on the surface of the resin base material 11. FIG.

(C) The surface-treated copper foil 1 according to the present embodiment is used when the thickness of the adhesive layer provided on the resin base material 11 bonded to the surface-treated copper foil 1 when the laminated plate 10 is formed is thin. It is particularly effective. For example, it is particularly effective when the thickness of the adhesive layer is 25 μm or less. That is, even if the surface-treated copper foil 1 according to the present embodiment is a case where the thickness of the adhesive layer is thin, the convex portion formed by the plated particles 3a is bonded to the roughened surface of the surface-treated copper foil 1. It can suppress penetrating the agent layer. Therefore, the effect (b) can be further obtained.

(D) Moreover, in FPC formed with the laminated board 10 using the surface-treated copper foil 1 by suppressing that a part of surface-treated copper foil 1 remains on the surface of the resin base material 11, The wiring pitch can be made narrower. That is, a fine copper wiring can be formed. Further, even when fine copper wiring is formed, for example, occurrence of a short circuit can be suppressed, and the reliability of the FPC can be further improved. Thus, the surface-treated copper foil 1 according to the present embodiment is particularly effective when used for an FPC that forms fine copper wiring.

(E) By making the thickness of the roughened copper plating layer 3 0.03 μm or more and 1.1 μm or less, the horizontal average particle diameter of the plating particles 3 a and the average particle diameter of the plating particles 3 a in the growth direction, The growth angle θ of the plating particle 3a can be ensured in a desired range. Therefore, the effects (a) to (d) can be obtained more reliably.

(F) The laminated board 10 formed using the surface-treated copper foil 1 according to the present embodiment is particularly effective when used for FPC. The FPC formed using the surface-treated copper foil 1 according to the present embodiment has high identification ease through the resin base material 11 at the location where the surface-treated copper foil 1 is removed, and the surface-treated copper foil 1 is removed. Thus, the copper wiring can be easily recognized through the resin base material 11 at the spot, and the mounting workability can be improved. Moreover, it can suppress that the copper wiring formed by removing the predetermined location of the surface treatment copper foil 1 by an etching etc. peels from the resin base material 11. FIG.

(Other embodiments of the present invention)
As mentioned above, although one Embodiment of this invention was described concretely, this invention is not limited to the above-mentioned embodiment, In the range which does not deviate from the summary, it can change suitably.

  Although the above-mentioned embodiment demonstrated the case where the surface-treated copper foil 1 was provided with the base plating layer 4, it is not limited to this. That is, the base plating layer 4 may not be provided. Also by this, by optimizing the plating conditions such as the current density and the plating time of the plating treatment for forming the roughened copper plating layer 3, the horizontal average particle diameter of the plating particles 3a and the growth direction of the plating particles 3a can be improved. Each of the particle diameter and the growth angle θ of the plating particle 3a can be set to a desired range.

  Further, for example, the surface-treated copper foil 1 may include a plating particle drop-off suppressing layer provided so as to cover at least the upper surface of the roughened copper plating layer 3. The plating particle drop-off suppressing layer is preferably formed of, for example, a copper plating layer. The thickness of the plating particle drop-off suppressing layer is preferably 0.05 μm or more and 0.3 μm or less, for example.

  Although the above-mentioned embodiment demonstrated the case where the antirust layer 5 was equipped with Ni plating layer (or Ni alloy plating layer), it is not limited to this. That is, the rust preventive layer 5 may not include the Ni plating layer. In this case, it is preferable to increase the thickness of the Zn plating layer compared to the case where the Ni plating layer is provided. For example, the thickness of the Zn plating layer is preferably 5 nm or more and 20 nm or less.

  Further, for example, a rust prevention layer (hereinafter also referred to as a “back surface rust prevention layer”) is provided on the main surface of the copper foil base 2 opposite to the main surface on which the roughened copper plating layer 3 is provided. It may be done. The back surface rust preventive layer can impart to the surface treated copper foil 1 heat resistance, chemical resistance, etc. that can withstand the amount of heat applied to the surface treated copper foil 1 in the manufacturing process of the laminated plate 10 and FPC, for example. It only has to be configured. For example, the back surface rust prevention layer includes a Ni plating layer (or Ni alloy plating layer), a Zn plating layer (or Zn alloy plating layer), and a chromate treatment layer in order from the copper foil base material 2 side. Preferably it is. The Ni plating layer (or Ni alloy plating layer) may not be provided. Moreover, the thickness of a back surface antirust layer should just be the thickness which can provide desired heat resistance, chemical-resistance, etc. to the surface treatment copper foil 1. FIG. However, since the back surface rust preventive layer is difficult to be etched, the thickness of the back surface rust preventive layer is, for example, after the back surface rust preventive layer is removed from the laminate 10 by etching in the FPC manufacturing process, It is preferable that it is the thickness which can suppress that a part of rust prevention layer remains. That is, it is preferable that the thickness is such that the etching residue of the back surface rust preventive layer can be suppressed. For example, the thickness of the back surface rust prevention layer is preferably thinner than the thickness of the rust prevention layer 5. The back surface antirust layer can be formed simultaneously with the above-described antirust layer forming step. For example, the Ni plating layer of the back surface rust prevention layer can be formed simultaneously with the formation of the Ni plating layer of the rust prevention layer 5. In addition, you may perform formation of a back surface antirust layer after the above-mentioned antirust layer formation process is complete | finished.

  Moreover, before performing a base plating layer formation process, a roughening copper plating layer formation process, a rust prevention layer formation process, etc., respectively, the cleaning which cleans the surface of the copper foil base material 2 or the roughening copper plating layer 3 as needed Processing may be performed. For example, the adhesion between the surface-treated copper foil 1 and the resin base material 11 in the laminated plate 10 can be further improved by performing a cleaning treatment before the roughened copper plating layer forming step.

  As the cleaning treatment, for example, electrolytic degreasing treatment and pickling treatment may be performed. The electrolytic degreasing treatment can be performed by cathodic electrolytic degreasing using an alkaline aqueous solution containing sodium hydroxide or the like. The pickling treatment neutralizes the alkali component remaining on the surfaces of the copper foil base 2 and the roughened copper plating layer 3 and removes the oxide film. The pickling treatment can be performed by immersing the copper foil base material 2 (the copper foil base material 2 provided with the roughened copper plating layer 3) in an acidic aqueous solution containing, for example, sulfuric acid or citric acid. . The pickling treatment may be performed using an etchant that etches copper.

  Although the above-mentioned embodiment demonstrated the case where the laminated sheet 10 was formed by bonding the surface-treated copper foil 1 on both main surfaces of the resin base material 11, it is not limited to this. That is, the laminated board 10 should just be formed by bonding the surface-treated copper foil 1 on at least one main surface of the resin base material 11.

  In the above-described embodiment, the surface-treated copper foil 1 and the resin base material 11 are bonded using a vacuum press machine, but the present invention is not limited to this. For example, the laminate 10 may be formed by bonding the surface-treated copper foil 1 and the resin base material 11 using an adhesive.

  In the above-mentioned embodiment, although the case where FPC was formed from the laminated board 10 comprised using the surface treatment copper foil 1 was demonstrated, it is not limited to this. The surface-treated copper foil 1 according to the present embodiment can be used for an electromagnetic wave shield for plasma display, an antenna of an IC card, and the like. Also in this case, the above-described effect can be obtained.

  Next, examples of the present invention will be described, but the present invention is not limited thereto.

<Preparation of sample>
(Sample 1)
First, a rolled copper foil formed of tough pitch copper (TPC) and having a thickness of 17 μm was prepared as a copper foil base material.

The copper foil base material was subjected to electrolytic degreasing treatment and pickling treatment to clean the surface of the copper foil base material. Specifically, first, electrolytic degreasing treatment was performed using an aqueous solution containing 40 g / L of sodium hydroxide and 60 g / L of sodium carbonate. At this time, the liquid temperature was 45 ° C., the current density was 30 A / dm ² , and the treatment time was 7 seconds. After the electrolytic degreasing treatment was completed, the copper foil base material was washed with water. Then, the copper foil base material was immersed in an aqueous solution containing 200 g / L sulfuric acid and having a liquid temperature of 25 ° C. for 10 seconds to perform pickling. After the pickling treatment was completed, the copper foil base material was washed with water.

Next, a base plating layer having a thickness of 0.5 μm was formed on any main surface of the copper foil base material. Specifically, the plating solution for forming the base plating layer (base plating solution) includes copper sulfate pentahydrate 150 g / L, sulfuric acid 50 g / L, and hydrochloric acid 0.3 ml / L. An aqueous solution was prepared. The base plating solution temperature is set to 35 ° C., the current density is set to 8 A / dm ² , the plating time is set to 8 seconds, and any main surface of the copper foil base material is subjected to electrolytic plating treatment. A plating layer was formed.

After forming the base plating layer, the copper foil substrate was washed with water. Thereafter, a roughened copper plating layer having a thickness of 0.03 μm was formed on the base plating layer. Specifically, an aqueous solution containing 100 g / L of copper sulfate pentahydrate, 150 g / L of sulfuric acid, and 50 g / L of iron sulfate heptahydrate was prepared as a roughened copper plating solution. And the liquid temperature of the roughening copper plating solution was set to 30 ° C., the current density was set to 60 A / dm ² , the plating time was set to 0.5 seconds, and electrolytic plating treatment was performed to form a roughened copper plating layer.

  After forming the roughened copper plating layer, the copper foil base material was washed with water. Thereafter, a rust preventive layer was formed on the roughened copper plating layer. Specifically, as a rust preventive layer, in order from the copper foil base material side, a Ni plating layer having a thickness of 20 nm, a Zn plating layer having a thickness of 4 nm, and a chromate film having a thickness of 4 nm, And a silane coupling treatment layer having an extremely thin thickness.

Specifically, an Ni plating layer is formed by electrolytic plating using an aqueous solution (Ni plating solution) containing 300 g / L of nickel sulfate hexahydrate, 45 g / L of nickel chloride, and 40 g / L of boric acid. Formed. At this time, the temperature of the Ni plating solution was 50 ° C., the current density was 2.5 A / dm ² , and the plating time was 5 seconds. After forming the Ni plating layer, the copper foil substrate was washed with water. Thereafter, a Zn plating layer was formed using an aqueous solution (Zn plating solution) containing 90 g / L of zinc sulfate heptahydrate and 70 g / L of sodium sulfate. At this time, the temperature of the Zn plating solution was 30 ° C., the current density was 1.8 A / dm ² , and the plating time was 4 seconds. After forming the Zn plating layer, the copper foil substrate was washed with water. Subsequently, a trivalent chromium chemical conversion treatment was performed to form a chromate film. After forming the chromate film, the copper foil substrate was washed with water. And after immersing the copper foil base material in which the chromate film | membrane was formed in the silane coupling liquid whose concentration of 3-aminopropyl trimethoxysilane is 5% and whose liquid temperature is 25 degreeC for 5 second, it is 200 degreeC immediately. A silane coupling treatment layer was formed by drying at a temperature of.

  Moreover, the antirust layer (back surface antirust layer) was formed on the main surface of the copper foil base material on the opposite side to the main surface on which the roughened copper plating layer was formed. Specifically, a Ni plating layer having a predetermined thickness, a Zn plating layer having a predetermined thickness, and a chromate treatment layer having a predetermined thickness were formed in this order from the copper foil base material side as a back surface rust prevention layer. . In addition, the formation method of Ni plating layer, Zn plating layer, and chromate treatment layer is the same as that of the Ni plating layer, Zn plating layer, and chromate treatment layer as a rust prevention layer provided on the roughened copper plating layer. In this way, a surface-treated copper foil was produced and used as Sample 1.

(Samples 2 to 58)
In each of samples 2 to 58, the concentration of iron sulfate heptahydrate in the roughened copper plating solution, the temperature of the roughened copper plating solution, the plating time of the plating treatment for forming the roughened copper plating layer, the current density, etc. Changed as appropriate. In Samples 28 to 30 and Samples 56 to 58, no base plating layer was provided. Moreover, in the samples 28-30, when forming a roughened copper plating layer, compared with the samples 13-15, the density | concentration of the iron sulfate heptahydrate contained in a roughened copper plating solution is made high, and it roughens. The liquid temperature and current density of the copper plating solution were increased, and the plating time was shortened. In each of Samples 56 to 58, when the roughened copper plating layer was formed, the concentration of iron sulfate heptahydrate contained in the roughened copper plating solution was increased as compared with Samples 37 to 39, and the roughened copper plating layer was formed. The plating temperature and current density were increased, and the plating time was shortened. Other than this, a surface-treated copper foil was prepared in the same manner as Sample 1. These are designated as Samples 2 to 58, respectively.

<Calculation of horizontal average particle diameter of plating particles>
For each of the surface-treated copper foils of Samples 1 to 58, the average particle diameter in the horizontal direction of the plated particles contained in the roughened copper plating layer was calculated. Specifically, an SEM obtained by observing the upper surface of the roughened copper plating layer (the roughened surface of the surface-treated copper foil) from directly above the roughened copper plating layer at an observation magnification of 30000 times by the SEM method. Ten plating particles were arbitrarily extracted from the image, and the particle diameter (maximum diameter) of the extracted plating particles was measured. And the average value of the particle diameter of the measured plating particle was computed, and this was made into the average particle diameter of the horizontal direction of a plating particle. The calculation results are shown in Table 3 and Table 4 below, respectively.

<Calculation of average particle diameter in the growth direction of plating particles>
For each surface-treated copper foil of Samples 1 to 58, the average particle diameter in the growth direction of the plated particles contained in the roughened copper plating layer was calculated. Specifically, 30 plating particles were arbitrarily extracted from the SEM image obtained by observing the longitudinal section of the roughened copper plating layer at an observation magnification of 10,000 times by the SEM method. In the extracted longitudinal section of the plated particles, the vertex and the midpoint of the bottom were detected, and the particle diameter in the growth direction of the plated particle (distance between the vertex and the midpoint of the bottom) was measured. And the average value of the particle diameter of the growth direction of the measured plating particle was computed. The calculation results are shown in Tables 3 and 4 below.

<Measurement of plating particle growth angle>
The growth angle of the plating particles contained in the roughened copper plating layer was measured for each of the surface-treated copper foils of Samples 1 to 58. Specifically, 30 plating particles were arbitrarily extracted from the SEM image obtained by observing the longitudinal section of the roughened copper plating layer at an observation magnification of 10,000 times by the SEM method. In the extracted longitudinal section of the plated particles, the vertex and the midpoint of the bottom were detected, respectively, and the growth direction of the plated particle (the direction from the midpoint of the bottom of the plated particle to the vertex) was detected. And the angle (growth angle of a plating particle) which the growth direction of a plating particle and the main surface of a copper foil base material make was measured. And in each sample, the average value of the growth angle of the plating particles was calculated, and the calculation results are shown in Tables 3 and 4 below.

<Production of laminated plate>
On both main surfaces of the resin base material, the surface-treated copper foils of Samples 1 to 58 were bonded to produce a laminate. In addition, as a resin base material, a thermoplastic polyimide (TPI) layer (adhesive layer) having a thickness of 1.4 μm was provided on each main surface, and a polyimide film having a total thickness of 12.5 μm was used. .

  First, each surface-treated copper foil of Samples 1 to 58 was cut into a predetermined size (length 100 mm × width 60 mm) and cut out. Then, two surface-treated copper foils cut from the same sample are opposed to each other with the resin base material sandwiched therebetween, and the roughened copper plating layer of each surface-treated copper foil is opposed to the resin base material, respectively. A surface-treated copper foil was disposed on both surfaces of the material to produce a laminate. Then, using a vacuum press machine, a pressure was applied to the laminate for 15 minutes under a condition of 280 ° C. with a pressing pressure of 5 MPa, and the surface-treated copper foil and the resin base material were bonded to form a laminate.

<Evaluation of adhesion>
About the laminated board produced using each surface-treated copper foil of samples 1 to 58, as an evaluation of adhesion between the surface-treated copper foil and the resin base material, peel when the surface-treated copper foil is peeled from the resin base material Intensity measurements were taken.

  The peel strength was measured as follows. First, a masking tape having a width of 1 mm was pasted on one main surface (any surface-treated copper foil provided in the laminate) of each laminate produced using each sample. Moreover, the masking tape was stuck on the whole surface of the other main surface of each laminated board. And each laminated board which stuck the masking tape was spray-etched using ferric chloride on the conditions of 35 degreeC or more and 50 degrees C or less (this example 45 degreeC), and surface-treated copper from a laminated board A predetermined portion of the foil (a portion where the masking tape was not applied) was removed. Thereafter, the masking tape was removed. Subsequently, the strength when the surface-treated copper foil was peeled from the resin base material was measured. Specifically, using an autograph, a surface-treated copper foil etched to a width of 1 mm is formed at an angle of 90 ° from the resin substrate (the angle formed by the peeled surface-treated copper foil and the resin substrate. The peel load when the surface-treated copper foil was pulled from the resin substrate at a speed of 50 mm / min was measured, and this was taken as the peel strength. It means that adhesiveness is so high that the value of the measured peel strength is large. The measurement results of peel strength are shown in Table 3 and Table 4 below, respectively.

<Evaluation of transparency>
For the laminates formed using the surface-treated copper foils of Samples 1 to 58, respectively, as the evaluation of the transparency of the resin base material after removing the surface-treated copper foil as each sample from the laminate, after removing the copper foil The HAZE value of the resin base material was measured.

  Specifically, the laminate produced using each sample was spray-etched with ferric chloride under conditions of 35 ° C. or more and 50 ° C. or less (45 ° C. in this example), and the laminate All the surface-treated copper foil was removed. That is, the entire surface of both surfaces (both main surfaces) of the resin base material was exposed. And about each of the resin base material from which the surface treatment copper foil was removed, the HAZE value was measured using haze-gard plus made by Toyo Seiki Seisakusho. It means that the smaller the HAZE value, the higher the transparency of the resin substrate after removing the copper foil. The measurement results of the HAZE value are shown in Table 3 and Table 4 below, respectively.

<Evaluation of the rest>
About the laminated board formed using each surface-treated copper foil of samples 1-58, after removing the surface-treated copper foil which is each sample from a laminated board, surface-treated copper foil does not remain on the surface of a resin base material, respectively. It was evaluated whether or not. That is, it was evaluated whether or not the root residue was generated on the resin base material after the copper foil was removed.

  Specifically, a masking tape having a width of 1 mm was pasted on each main surface (any one of the surface-treated copper foils provided in the laminate) of the laminate produced using each sample. Moreover, the masking tape was stuck on the whole surface of the other main surface of each laminated board. And each laminated board which stuck the masking tape was spray-etched using ferric chloride on the conditions of 35 degreeC or more and 50 degrees C or less (this example 45 degreeC), and surface-treated copper from a laminated board A predetermined portion of the foil (a portion where the masking tape was not applied) was removed. Thereafter, the masking tape was removed. Subsequently, the surface-treated copper foil etched to have a width of 1 mm is observed from directly above by the SEM method, the surface-treated copper foil having a width of 1 mm, and the resin base material where the surface-treated copper foil has been removed, SEM image containing was obtained. Then, in the obtained SEM image, whether or not the surface-treated copper foil that should be etched and removed does not remain on the resin base material, that is, whether or not the root residue of the surface-treated copper foil has occurred. It was confirmed. At this time, it is a region of the resin base material after the removal of the copper foil, and a region in the vicinity of the surface-treated copper foil having an arbitrary length of 10 mm along the length direction of the surface-treated copper foil having a width of 1 mm (surface-treated copper). The boundary between the foil and the resin substrate was confirmed. And the sample whose surface treatment copper foil which should be removed originally on the resin base material should have a maximum diameter of less than 5 μm is a pass (◯), and the sample whose surface treatment copper foil has a maximum diameter of 5 μm or more remains. Was evaluated as a failure (x). The evaluation results of the remaining roots of the surface-treated copper foil are shown in Table 3 and Table 4 below, respectively.

<Evaluation results>
From Samples 1 to 30, the average particle size in the horizontal direction of the plating particles contained in the roughened copper plating layer is 0.05 μm or more and 0.8 μm or less, and the average particle size in the growth direction of the plating particles is 0.05 μm or more and 1 It was confirmed that the desired transparency could be secured while maintaining the desired adhesion when the plating particle growth angle was 20 ° or more and 90 ° or less. Specifically, it was confirmed that the HAZE value of the resin base material after removing the copper foil can be made 80% or less while maintaining the peel strength at 0.7 N / mm or more. As a result, when electronic parts are mounted on FPCs formed using surface-treated copper foil, the copper wiring can be recognized through the resin substrate where the copper foil has been removed by visual inspection or a CCD camera, etc. It was confirmed that the mounting position can be easily positioned. Moreover, it was confirmed that the copper wiring is difficult to peel from the resin base material, and the reliability of the FPC can be improved.

  Moreover, the laminated board using the surface-treated copper foil of samples 1 to 30 is a part of the surface-treated copper foil (originally to be removed by etching) on the surface of the resin base material after removing the copper foil. It was confirmed that it was possible to suppress the remaining part). That is, it was confirmed that the occurrence of root residue can be suppressed. As a result, the FPC formed from the laminate using the surface-treated copper foils of Samples 1 to 30 can suppress the occurrence of a short circuit and increase the reliability of the FPC even when a fine copper wiring is formed. Confirmed that it can.

  From the comparison between Samples 13 to 15 and Samples 28 to 30 and the comparison between Samples 37 to 39 and Samples 56 to 58, iron sulfate heptahydrate in the roughened copper plating solution can be obtained without providing a base plating layer. By controlling the concentration of copper, the temperature of the roughened copper plating solution, the current density, and the plating time, the desired transparency is maintained while maintaining the desired adhesion, as in the case of providing a base plating layer. Confirmed that you can. Specifically, it was confirmed that the HAZE value of the resin base material after removing the copper foil can be made 80% or less while maintaining the peel strength at 0.7 N / mm or more.

  From Samples 31 to 39, when the average particle diameter in the horizontal direction of the plating particles is less than 0.05 μm, the average particle diameter in the growth direction of the plating particles and the growth angle of the plating particles are within a desired range. It was confirmed that the adhesion could not be maintained. Specifically, it was confirmed that the peel strength might be less than 0.7 N / mm.

  From the samples 40 to 42, if the average particle size in the growth direction of the plating particles is less than 0.05 μm, the average particle size in the horizontal direction of the plating particles and the growth angle of the plating particles are within the desired range. It was confirmed that the adhesion could not be maintained. Specifically, it was confirmed that the peel strength might be less than 0.7 N / mm.

  From Sample 43, if the growth angle of the plating particles is less than 20 °, the desired adhesion can be achieved even if the average particle diameter in the horizontal direction of the plating particles and the average particle diameter in the growth direction of the plating particles are within the desired ranges, respectively. It was confirmed that it may not be possible to maintain. Specifically, it was confirmed that the peel strength might be less than 0.7 N / mm.

  When the average particle diameter in the growth direction of the plating particles exceeds 1.2 μm from the samples 44 to 46, the copper foil is removed even if the average particle diameter in the horizontal direction of the plating particles and the growth angle of the plating particles are within a predetermined range. It was confirmed that the transparency of the subsequent resin base material was lowered and the desired transparency could not be ensured. Specifically, it was confirmed that the HAZE value of the resin base material after removing the copper foil may exceed 80%.

  When the average particle diameter in the growth direction of the plated particles exceeds 1.2 μm from Samples 37 to 40, Samples 44 to 46, and Samples 53 to 58, the surface of the resin base material after removing the copper foil is originally removed by etching. It was confirmed that a part of the surface-treated copper foil to be left may remain.

  From Samples 47 to 55, when the average particle diameter in the horizontal direction of the plating particles exceeds 0.8 μm, the desired transparency can be obtained even if the average particle diameter in the growth direction of the plating particles and the growth angle of the plating particles are within a desired range. It was confirmed that there is a case that the sex cannot be secured. Specifically, it was confirmed that the HAZE value of the resin base material after removing the copper foil may exceed 80%.

<Preferred embodiment of the present invention>
Hereinafter, preferred embodiments of the present invention will be additionally described.

[Appendix 1]
According to one aspect of the invention,
A copper foil base material;
A roughened copper plating layer that is provided on at least one main surface of the copper foil base material and includes a plurality of plating particles grown in a predetermined growth direction, and
The average value of the particle diameter along the principal surface of the copper foil base material of the plating particles is 0.05 μm or more and 0.8 μm or less,
The average value of the particle diameter along the growth direction of the plating particles is 0.05 μm or more and 1.2 μm or less,
Provided is a surface-treated copper foil in which an angle formed by the growth direction of the plating particles and the main surface of the copper foil base is 20 ° or more and 90 ° or less.

[Appendix 2]
The surface-treated copper foil of Appendix 1, preferably,
The peel strength when peeling the surface-treated copper foil from the resin substrate after bonding the surface-treated copper foil to the resin substrate is 0.7 N / mm or more,
The surface-treated copper foil is disposed on both main surfaces of the resin substrate so that the surface-treated copper foil faces the resin substrate and the roughened copper plating layer faces the resin substrate. After bonding, the HAZE value of the resin base material obtained by removing the surface-treated copper foil from both main surfaces of the resin base material is 80% or less.

[Appendix 3]
The surface-treated copper foil according to appendix 1 or 2,
The roughened copper plating layer has an average thickness of 0.03 μm or more and 1.1 μm or less.

[Appendix 4]
According to another aspect of the invention,
A surface-treated copper foil provided with a roughened copper plating layer that is provided on at least one main surface of the copper foil base material and the copper foil base material and includes a plurality of plating particles grown in a predetermined growth direction, and
A resin base material bonded to the surface-treated copper foil so as to face the roughened copper plating layer,
The average value of the particle diameter along the principal surface of the copper foil base material of the plating particles is 0.05 μm or more and 0.8 μm or less,
The average value of the particle diameter along the growth direction of the plating particles is 0.05 μm or more and 1.2 μm or less,
There is provided a laminated board in which an angle formed by the growth direction of the plating particles and the main surface of the copper foil base material is 20 ° or more and 90 ° or less.

[Appendix 5]
The laminated board according to appendix 4, preferably,
The resin base material is provided with an adhesive layer for bonding the surface-treated copper foil,
The adhesive layer has a thickness of 25 μm or less.

DESCRIPTION OF SYMBOLS 1 Surface treatment copper foil 2 Copper foil base material 3 Roughening copper plating layer 3a Plating particle 11 Resin base material

Claims (4)

A copper foil base material;
A roughened copper plating layer that is provided on at least one main surface of the copper foil base material and includes a plurality of plating particles grown in a predetermined growth direction, and
The average value of the particle diameter along the principal surface of the copper foil base material of the plating particles is 0.05 μm or more and 0.8 μm or less,
The average value of the particle diameter along the growth direction of the plating particles is 0.05 μm or more and 1.2 μm or less,
The surface-treated copper foil whose angle which the growth direction of the said plating particle and the main surface of the said copper foil base material make is 20 degrees or more and 90 degrees or less. According to the surface-treated copper foil to <br/> claim 1 peel strength is 0.7 N / mm or more when peeling off the surface treated copper foil after bonding the resin substrate from the resin substrate Surface treated copper foil. The surface-treated copper foil according to claim 1 or 2, wherein an average thickness of the roughened copper plating layer is 0.03 µm or more and 1.1 µm or less. A surface-treated copper foil provided with a roughened copper plating layer that is provided on at least one main surface of the copper foil base material and the copper foil base material and includes a plurality of plating particles grown in a predetermined growth direction, and
A resin base material bonded to the surface-treated copper foil so as to face the roughened copper plating layer,
The average value of the particle diameter along the principal surface of the copper foil base material of the plating particles is 0.05 μm or more and 0.8 μm or less,
The average value of the particle diameter along the growth direction of the plating particles is 0.05 μm or more and 1.2 μm or less,
The laminated board whose angle formed by the growth direction of the said plating particle and the main surface of the said copper foil base material is 20 degrees or more and 90 degrees or less.