Laminated board and method for manufacturing the same

Abstract

To provide: a laminate which, even when the frequency of a transmission signal is 10 GHz or more, can reduce a transmission loss by suppressing a conductor loss and with which good adhesion between a copper foil and a resin film can be obtained; and a method for producing the same.SOLUTION: Provided is a laminate such as a copper-clad laminate 5 and the like obtained by sticking an aluminum foil 1 and a polyether ether ketone resin film 3 by direct lamination. Glossiness on the lamination / sticking surface 2 of the copper foil 1 with the polyether ether ketone resin film 3 is configured as 30 to 90 when measured according to the specifications of JIS Z 8741-1997, an arithmetic average height Sa on the lamination / sticking surface 2 is configured as 0.2 μm to 0.4 μm, and a maximum height Sz on the lamination / sticking surface 2 is configured as 4 μm to 6 μm. Because the signal transmission path is shortened by smoothing the lamination / sticking surface 2, there is little scattering of transmission signals due to large irregularities on the lamination / sticking surface 2 and, even when the frequency of the transmission signal becomes 10 GHz or larger, the conductor loss can be suppressed by reducing manifestation of the skin effect.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a laminated board used as a copper-clad laminate (CCL), a flexible printed wiring board (FPC), etc., which are the basis of all circuits and printed boards, and a method for manufacturing the same.

Background Art

[0002] In recent years, in computer devices, mobile communication terminals, and other electronic devices, in order to improve the data processing speed and communication speed and enable stress-free large-capacity data processing, a significant increase in the data processing speed and communication speed has been required. To meet this requirement, in the field of printed boards, research has been conducted to minimize the transmission loss of high-frequency signals (see Patent Documents 1, 2, 3, and 4).

[0003] There are various factors contributing to the transmission loss of the high-frequency signals under study, and conductor loss is one of them. Regarding this conductor loss, when the frequency of the transmission signal increases, the skin effect, where the transmission signal flows on the circuit surface of the printed circuit board, appears, the physical effective cross-sectional area through which the transmission signal flows decreases, the resistance increases, and signal delay of the transmission signal occurs. As a result, it becomes difficult to obtain the arithmetic speed as designed, or malfunction due to the knock-on phenomenon of the transmission signal may occur. Thus, the higher the speed of the signal to be transmitted, the greater the conductor loss of the circuit, and the problem that signal transmission becomes difficult arises.

[0004] To solve such problems, Patent Document 1 discloses a copper foil for high-frequency circuits that can suppress transmission loss when used as a conductor for high-frequency circuits. This copper foil for high-frequency circuits is a copper foil for high-frequency circuits obtained by roughening at least one side of an electrolytic copper foil, and is laminated and formed so that the roughened surface of the electrolytic copper foil contacts an insulating resin base material to form a copper-clad laminate. When the electrolytic copper foil is made into a copper layer with a thickness of 3 μm in terms of weight conversion by half etching, the resistivity of the copper layer is 2.2×10 -8 Ωm or less, preferably 2.0×10 -8It is characterized by being below Ωm. As a roughening treatment method for electrolytic copper foil, it is not particularly limited, and examples thereof include a method of forming a roughening layer such as copper on the surface of the electrolytic copper foil.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, even if the resistivity of the copper layer is suppressed by using the copper foil for high-frequency circuits of Patent Document 1, when the frequency of the transmission signal becomes 10 GHz or higher, especially 15 GHz or higher, the skin effect becomes remarkable, so there is a problem that the transmission loss increases due to the presence of the roughened surface of the electrolytic copper foil.

[0007] To solve this problem, a method of suppressing transmission loss by omitting the roughened surface of the electrolytic copper foil can be considered. However, if the roughened surface of the electrolytic copper foil is omitted, the adhesion between the electrolytic copper foil and the resin base material decreases, and a major problem that these electrolytic copper foils and resin base materials peel off or separate newly occurs.

[0008] The present invention has been made in view of the above, and an object thereof is to provide a laminate that can suppress conductor loss and reduce transmission loss even when the frequency of a transmission signal is 10 GHz or higher, and can obtain good adhesion between a copper foil and a resin film, and a method for manufacturing the same.

Means for Solving the Problems

[0009] In the present invention, in order to solve the above problems, a copper foil and a polyetheretherketone resin film are directly laminated and attached, when the glossiness of the laminated and attached surface of the copper foil and the polyetheretherketone resin film is measured in accordance with the provisions of JIS Z 8741-1997, it is 30 or more and 90 or less, the arithmetic mean height Sa of the laminated and attached surface of the copper foil and the polyetheretherketone resin film is 0.2 μm or more and 0.4 μm or less, and the maximum height Sz of the laminated and attached surface of the copper foil and the polyetheretherketone resin film is 4 μm or more and 6 μm As follows, A filler is compounded into a polyetheretherketone resin film which is characterized by this.

[0010] When measuring the adhesive strength when peeling the copper foil in accordance with JIS Z 0237:2009, it is preferable that the adhesive strength is 6 N / cm or more. Further, when the copper foil is etched to produce a microstrip line having a length of 10 cm and an impedance of 50 Ω and the transmission characteristics at 30 GHz are measured under the conditions of a temperature of 25 °C and a humidity of 50%, it is preferable that the transmission characteristics are -3.9 dB or less.

[0011] Further, it is preferable that the relative dielectric constant of the polyetheretherketone resin film at 28 GHz is 3.7 or less and the dielectric loss tangent is 0.006 or less. Further, it is good that the linear expansion coefficient of the polyetheretherketone resin film is 40 ppm / °C or less. Further, it is good that the crystallinity of the polyetheretherketone resin film is 5% or more and 30% or less.

[0012] Further, the polyetheretherketone resin film can be made into an alloy film with other resins. In addition, the other resin alloyed with the polyetheretherketone resin film can be at least one of a polyamideimide resin, a polyphenylene ether resin, a polyetherimide resin, a polyethersulfone resin, a polysulfone resin, a polytetrafluoroethylene resin, and a perfluoroalkoxy resin.

[0013] Further, the filler is preferably at least one of mica, talc, boron nitride, and silica.

[0014] In addition, in the present invention, in order to solve the above problems, Claims 1 to 7 a method for manufacturing a laminate according to any one of the above, a polyetheretherketone resin film is laminated on the laminated attachment surface of the copper foil, and the copper foil and the polyetheretherketone resin film are thermocompression bonded and attached at a temperature of -20°C or higher and +10°C or lower than the melting point of the polyetheretherketone resin film.

[0015] Note that corona treatment, plasma treatment, or ultraviolet treatment can be performed on at least one of the laminated attachment surface of the copper foil and the surface to be laminated and attached of the polyetheretherketone resin film. In addition, the storage elastic modulus during the thermocompression bonding of the polyetheretherketone resin film can be 5×10 5 Pa or more and 5×10 7 Pa or less.

[0016] Here, the copper foil in the claims may be either an electrolytic copper foil or a rolled copper foil, and can be directly laminated and attached to one or both sides of the polyetheretherketone resin film. In addition, the polyetheretherketone resin film can be formed from a molding material containing at least a polyetheretherketone resin. Various fillers can be added to the molding material in addition to the polyetheretherketone resin. Furthermore, the laminate according to the present invention can be used for a copper-clad laminate, a high-frequency printed circuit using a frequency of 10 GHz or higher, and the like.

[0017] According to the present invention, the glossiness on the laminated adhesion surface of the copper foil is set to be 30 or more and 90 or less, the arithmetic mean height Sa on the laminated adhesion surface of the copper foil is set to be 0.2 μm or more and 0.4 μm or less, and the maximum height Sz on the laminated adhesion surface is set to be 4 μm or more and 6 μm or less. Therefore, the transmission signal is less scattered due to large unevenness on the copper foil laminated adhesion surface. Further, since a polyetheretherketone resin film having excellent metal adhesion is used, the copper foil and the polyetheretherketone resin film are less likely to peel or separate.

Advantages of the Invention

[0018] According to the present invention, even when the frequency of the transmission signal is 10 GHz or more, there is an effect that conductor loss can be suppressed and transmission loss can be reduced. Further, there is an effect that good adhesion between the copper foil and the polyetheretherketone resin film can be obtained. In addition, since a filler is compounded into the polyetheretherketone resin film, the properties of the polyetheretherketone resin film can be improved.

[0019] According to the invention described in claim 2, since the relative permittivity of the polyetheretherketone resin film at 28 GHz is 3.7 or less and the dielectric tangent is 0.006 or less, it contributes to the realization of high-speed communication utilizing the high-frequency band. According to the invention described in claim 3, since the linear expansion coefficient of the polyetheretherketone resin film is 40 ppm / °C or less, the possibility that the copper foil or the polyetheretherketone resin film warps and peels off can be eliminated.

[0020] According to the invention described in claim 4, since the crystallinity of the polyetheretherketone resin film is 5% or more and 30% or less, there are few problems with the solder heat resistance of the polyetheretherketone resin film. Further, it is possible to expect to ensure the mechanical strength that can be used as a circuit board. According to the invention described in claim 5 or 6, since the polyetheretherketone resin film is an alloy film, it becomes possible to impart new performance and functions to the polyetheretherketone resin film.

[0021] According to Claim 7According to the invention, When mica or silica is compounded as a filler into the polyetheretherketone resin film, improvement in the strength, dimensional stability, heat resistance, insulation property, chemical resistance, water resistance, etc. of the polyetheretherketone resin film can be expected. Further, when boron nitride is compounded, improvement in the heat dissipation property and insulation property of the polyetheretherketone resin film can be expected. When silica is compounded, it becomes possible to improve the dimensional stability, heat resistance, chemical resistance, water resistance, etc.

[0022] According to the invention described in Claim 8, Since the copper foil and the polyetheretherketone resin film are thermocompression-bonded and attached, there is no need to bond the copper foil and the polyetheretherketone resin film with an adhesive, and a reduction in the materials required for manufacturing can be expected. Further, while forming a seed layer on the polyetheretherketone resin film and laminating and forming a copper foil on this seed layer, since there is no need to make these seed layer and copper foil into a metal layer either, a reduction in the materials required for manufacturing can be expected, and in addition, it becomes possible to shorten the manufacturing time.

[0023] According to Claim 9 According to the invention, by performing corona treatment, it becomes possible to improve the adhesiveness between the copper foil and the polyetheretherketone resin film. Further, by performing plasma treatment, it becomes possible to improve the adhesiveness and cleaning. Further, by performing ultraviolet treatment, improvement in cleaning becomes possible. According to Claim 10 According to the invention, since the storage elastic modulus during the thermocompression bonding of the polyetheretherketone resin film is in the range of 5×10 5 Pa or more and 5×10 7 Pa or less, it is possible to prevent a situation in which the polyetheretherketone resin film softens and does not fuse.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0025] Hereinafter, referring to the drawings, preferred embodiments of the present invention will be described. As shown in FIG. 1, the laminated board in this embodiment is a copper-clad laminated board 5 having a two-layer structure in which a copper foil 1 and a polyether ether ketone resin film 3 are laminated and attached. The glossiness, arithmetic mean height Sa, and maximum height Sz on the laminated attachment surface 2 of the copper foil 1 with the polyether ether ketone resin film 3 are numerically limited respectively, contributing to the achievement of Goal 9 of the SDGs (Sustainable Development Goals adopted at the United Nations Summit, consisting of 17 global goals and 169 targets (achievement criteria) for sustainable development of the United Nations).

[0026] The copper foil 1 is made of, for example, an electrolytic copper foil which is a thin film manufactured to a thickness of 2 μm or more and 100 μm or less based on the principle of electrolytic plating. After the laminated attachment surface 2 of the copper foil 1 is directly laminated and thermocompression bonded to the surface 4 to be laminated of the polyether ether ketone (PEEK) resin film 3 without an adhesive or the like in between, it is formed on the wiring pattern of the conductive circuit during the manufacture of a flexible printed wiring board or the like. The thickness range of the copper foil 1 is specified to be 2 μm or more and 100 μm or less, preferably 10 μm or more and 50 μm or less. This is because when the thickness is less than 2 μm, it will cause problems in handling during manufacture and use, and when it exceeds 100 μm, it will take time for manufacture.

[0027] The laminated attachment surface 2 of the copper foil 1 can be either the front or back surface of the copper foil 1. In the case where the copper foil 1 is an electrolytic copper foil manufactured by an electrolytic production apparatus, a shiny (S) surface which is smooth and shiny on the drum-shaped cathode surface side and a matte (M) surface on the opposite side of this shiny surface are respectively formed on the electrolytic copper foil. Either of these shiny surface and matte surface can be used as the laminated attachment surface 2.

[0028] The glossiness on the laminated bonding surface 2 between the copper foil 1 and the polyetheretherketone resin film 3 is specifically the glossiness [GS(60°)]. From the perspective of suppressing the transmission loss of high-frequency signals, when measured in accordance with the provisions of JIS Z 8741-1997, it is preferably 30 or more and 90 or less, more preferably 38 or more and 80 or less. Here, the glossiness [GS(60°)] is a measure of the brightness obtained by irradiating the laminated bonding surface 2 of the copper foil 1 with a measurement light beam at an incident angle of 60° and measuring the intensity of the measurement light beam reflected back at a reflection angle of 60°. This glossiness can be measured using various measuring instruments (for example, the digital color discrimination sensor CZ-V20 series manufactured by Keyence Corporation, the product name IG-410 manufactured by Tokyo Glass Kikai Co., Ltd., etc.).

[0029] The arithmetic mean height Sa on the laminated bonding surface 2 between the copper foil 1 and the polyetheretherketone resin film 3 is defined by the international standard of ISO 25178. From the perspective of shortening the signal transmission path on the laminated bonding surface 2 and facilitating the quality evaluation of the copper foil 1, when measured, it is preferably 0.2 μm or more and 0.4 μm or less, more preferably 0.31 μm or more and 0.38 μm or less. This arithmetic mean height Sa can be measured using various measuring instruments (for example, the roughness meter / shape measuring machine VR series and VR-6000 series manufactured by Keyence Corporation, the 3D measurement laser microscope LEXT OLS4100 manufactured by Olympus Corporation, etc.).

[0030] The maximum height Sz on the laminated bonding surface 2 between the copper foil 1 and the polyetheretherketone resin film 3 is defined by the international standard of ISO 25178. From the perspective of shortening the signal transmission path together with Sa, when measured, it is preferably 4 μm or more and 6 μm or less, more preferably 4.3 μm or more and 4.8 μm or less. This maximum height Sz can also be measured using various measuring instruments (for example, the roughness meter / shape measuring machine VR series and VR-6000 series manufactured by Keyence Corporation, the 3D measurement laser microscope LEXT OLS4100 manufactured by Olympus Corporation, etc.).

[0031] Examples of such copper foil products include TQ-M7-VSP [product name, manufactured by Mitsui Mining & Smelting Co., Ltd.], 3EC-III [product name, manufactured by Mitsui Mining & Smelting Co., Ltd.], CF-T49A-DS-HD2-12 [product name, manufactured by Fukuda Metal Foil & Powder Co., Ltd.], and the like.

[0032] The polyetheretherketone resin film 3 is formed into a resin film with a thickness of 2 μm or more and 1000 μm or less, preferably 25 μm or more and 125 μm or less, by a melt extrusion molding method using a molding material containing a polyetheretherketone resin, which is excellent in at least electrical insulation properties, mechanical properties, adhesion, heat resistance, chemical resistance, radiation resistance, hydrolysis resistance, low water absorption, recyclability, and the like.

[0033] The polyetheretherketone resin is a crystalline resin, and the glass transition point measured by a differential scanning calorimeter is usually 130°C or more and 160°C or less, preferably 135°C or more and 155°C or less, and the melting point measured by a differential scanning calorimeter is usually 320°C or more and 360°C or less, preferably 330°C or more and 350°C or less. Generally, it is used in a form suitable for molding processes such as powder, granule, pellet, and granular forms.

[0034] The polyetheretherketone resin film 3 can be manufactured by known manufacturing methods such as a melt extrusion molding method, a calender molding method, or a casting method. However, from the viewpoints of handleability and simplification of equipment, it is most suitable to be continuously extrusion molded by the melt extrusion molding method. Here, the melt extrusion molding method is a molding method in which a molding material is melt-kneaded using a melt extrusion molding machine, and the polyetheretherketone resin film 3 is continuously extruded from a T-die at the tip of the melt extrusion molding machine for manufacturing.

[0035] Examples of polyetheretherketone resin products are not particularly limited, but include Victrex Powder series, Victrex Granules series [product name, manufactured by Victrex], Vestakeep series [product name, manufactured by Daicel-Evonik], Keytaspaire PEEK series [product name, manufactured by Solvay Specialty Polymers], and the like.

[0036] From the perspective of realizing high-speed communication by utilizing the high-frequency band, the relative permittivity of the polyetheretherketone resin film 3 is 3.7 or less at 28 GHz, preferably 2.0 or more and 3.7 or less, more preferably 2.0 or more and 3.6 or less. Further, the dielectric loss tangent (tanδ) of the polyetheretherketone resin film 3 is 0.006 or less, preferably 0.002 or more and 0.0055 or less, more preferably 0.002 or more and 0.0052 or less in order to realize high-speed communication by utilizing the high-frequency band. Although the measurement methods for these relative permittivity and dielectric loss tangent are not particularly limited, it is optimal to select the Fabry-Perot method or the cavity resonator perturbation method, which are excellent in high resolution.

[0037] In order to eliminate the possibility that the copper foil 1 and the polyetheretherketone resin film 3 are peeled off, the coefficient of linear thermal expansion (CTE) of the polyetheretherketone resin film 3 is 40 ppm / °C or less, preferably 10 ppm / °C or more and 40 ppm / °C or less, more preferably 15 ppm / °C or more and 30 ppm / °C or less. The coefficient of linear thermal expansion of this polyetheretherketone resin film 3 can be measured by a thermomechanical analyzer (TMA) conforming to JIS K 7197:1991, but for measurement in the thickness direction of 100 μm or less, a high-precision dilatometer (DIL) can be used. In the present application, a thermomechanical analyzer is used, and the coefficient of linear thermal expansion in the temperature range from 25°C to 125°C at a heating rate of 5°C / min is used.

[0038] The crystallinity of the polyetheretherketone resin film 3 is preferably 5% or more and 30% or less, more preferably 15% or more and 22% or less. This is because when the crystallinity of the polyetheretherketone resin film 3 is less than 5%, there is a problem with the solder heat resistance of the polyetheretherketone resin film 3. Conversely, when the crystallinity exceeds 30%, it becomes difficult to ensure the mechanical strength that can be used for a high-frequency circuit board.

[0039] The polyetheretherketone resin film 3 may be a thin film formed of a polyetheretherketone (PEEK) resin, or may be an alloy film with other resins in order to ensure new performance and functions. Specifically, it may be an alloy film of a polyetheretherketone resin and at least one of a polyamideimide (PAI) resin, a polyphenylene ether (PPE) resin, a polyetherimide (PEI) resin, a polyethersulfone (PES) resin, a polysulfone (PSU) resin, a polytetrafluoroethylene (PTFE) resin, and a perfluoroalkoxy (PFE) resin.

[0040] In the molding material of the polyetheretherketone resin film 3, various fillers can be added in addition to the above resins as long as the characteristics of the present invention are not impaired. For example, mica, talc, silica, boron nitride (BN), calcium carbonate, antioxidant, light stabilizer, ultraviolet absorber, plasticizer, lubricant, flame retardant, antistatic agent, heat resistance improver, inorganic compound, organic compound, etc. can be selectively added. As mica, non-swelling synthetic mica with few impurities and little change in dimensional stability, etc. is preferable. Also, as silica, amorphous silica is suitable.

[0041] Such a copper-clad laminate 5 including the copper foil 1 and the polyetheretherketone resin film 3 is a material for manufacturing a printed circuit board. When the copper foil 1 is etched to form a wiring pattern, it is used as a flexible printed wiring board or the like using a frequency of 10 GHz or higher, preferably 15 GHz or higher. The adhesion of the polyetheretherketone resin film 3 in this copper-clad laminate 5, in other words, the peel strength, is optimally 6 N / cm or more, preferably 6.7 N / cm or more when measured in accordance with JIS Z 0237:2009 (Adhesive Tape and Adhesive Sheet Test Methods) in order to ensure practicality and reliability.

[0042] The transmission characteristics of the copper-clad laminate 5 are preferably -3.9 dB or less, more preferably -3.2 dB or less when a microstrip line with a length of 10 cm and an impedance of 50 Ω is fabricated by etching the copper foil 1 and the transmission characteristics at 30 GHz are measured under the conditions of a temperature of 25 °C and a humidity of 50%. This is because low transmission loss can be expected if the transmission characteristics are in the range of -3.9 dB or less.

[0043] In the above configuration, when manufacturing the copper-clad laminate 5, the copper foil 1 having the above characteristics and the polyetheretherketone resin film 3 are prepared respectively, the laminated bonding surface 2 of the copper foil 1 is exposed, and the polyetheretherketone resin film 3 is directly overlapped and laminated. At this time, corona treatment for improving strength and adhesiveness, plasma treatment for improving strength, adhesiveness, and cleaning, or ultraviolet treatment for improving strength and cleaning can be preliminarily performed on at least one of the laminated bonding surface 2 of the copper foil 1 and the surface to be laminated and bonded 4 of the polyetheretherketone resin film 3 as required.

[0044] After laminating the copper foil 1 and the polyetheretherketone resin film 3, if these are sandwiched between a hot press or rolls, heated and pressed for thermocompression bonding, the copper foil 1 and the polyetheretherketone resin film 3 can be used to manufacture an integrated copper-clad laminate 5. The temperature of the thermocompression bonding at this time is preferably in the temperature range of -20 °C or more and +10 °C or less with respect to the melting point of the polyetheretherketone resin film 3. The melting point of the polyetheretherketone resin film 3 varies depending on the presence or absence of a filler in the molding material, etc. For example, when it is 340 °C, the temperature range of the thermocompression bonding is in the range of 320 °C or more and 350 °C or less.

[0045] This is based on the reason that when the melting point of the polyetheretherketone resin film 3 is less than -20°C, the polyetheretherketone resin on the laminated adhesion surface 4 does not melt. On the other hand, when the melting point of the polyetheretherketone resin film 3 exceeds +10°C, it is based on the reason that the polyetheretherketone resin may decompose violently. Also, the storage elastic modulus E' during the thermocompression bonding of the polyetheretherketone resin film 3 is 5×10 5 Pa or more and 5×10 7 Pa or less, preferably 1×10 6 Pa or more and 1×10 7 Pa or less is good. This is because when the storage elastic modulus E' is outside the range of 5×10 5 Pa or more and 5×10 7 Pa or less, the polyetheretherketone resin film 3 does not fuse without softening or softens too much and flows too much.

[0046] According to the above, the glossiness on the laminated adhesion surface 2 of the copper foil 1 is set to 30 or more and 90 or less, the arithmetic mean height Sa on the laminated adhesion surface 2 of the copper foil 1 is set to 0.2 μm or more and 0.4 μm or less, and the maximum height Sz on the laminated adhesion surface 2 is set to 4 μm or more and 6 μm or less for smoothing, so that the shortening of the signal transmission path can be achieved. Therefore, the transmission signal is less scattered due to large unevenness on the laminated adhesion surface 2 of the copper foil 1, and even when the frequency of the transmission signal is 10 GHz or more, the manifestation of the skin effect can be reduced and the conductor loss can be suppressed. By suppressing this conductor loss, the problem of the increase in transmission loss due to the presence of the roughened surface of the copper foil 1 can be effectively solved, the arithmetic speed as designed can be obtained, and malfunction due to the knock-on phenomenon of the transmission signal can also be avoided.

[0047] In addition, when the copper foil 1 is for 5G that handles high-frequency bands, the surface roughness needs to be refined more than ever. Therefore, although it may be difficult to smooth it only with the value of the maximum height Sz, since the glossiness and the arithmetic mean height Sa on the laminated attachment surface 2 are also numerically limited, the smoothing of the laminated attachment surface 2 can be surely realized. Furthermore, since a polyether ether ketone resin film 3 having excellent metal adhesion is selected instead of a mere thermoplastic resin film, the copper foil 1 and the polyether ether ketone resin film 3 do not peel or separate from each other even if the laminated attachment surface 2 of the copper foil 1 is not subjected to uneven processing and the anchor effect is not expected.

[0048] Next, FIG. 2 shows a second embodiment of the present invention. In this case, the number of copper foils 1 is increased, and a three-layer copper-clad laminate 5 is formed by sequentially laminating the copper foil 1, the polyether ether ketone resin film 3, and the copper foil 1 and then thermocompression bonding them. When the copper foil 1 is an electrolytic copper foil, the laminated attachment surface 2 of the electrolytic copper foil may be a shiny surface with gloss or a matte surface without gloss. Since the other parts are the same as those in the above embodiment, the description thereof is omitted.

[0049] In this embodiment as well, the same operational effects as those in the above embodiment can be expected. Moreover, since the copper-clad laminate 5 is made to be double-sided instead of single-sided, it is obvious that the versatility of the copper-clad laminate 5 can be remarkably improved.

[0050] In the above embodiment, the copper-clad laminate 5 is used as a material for a flexible printed wiring board, but it is not limited thereto. For example, it may be used as a material for an automotive collision prevention millimeter-wave radar device, an advanced driver assistance system (ADAS), artificial intelligence (AI), etc.

Example

[0051] Hereinafter, examples of the laminate and its manufacturing method according to the present invention will be described together with comparative examples. To manufacture double-sided copper-clad laminates for the examples and comparative examples, four types of copper foils shown in Table 1, namely electrolytic copper foils, two types of polyether ether ketone resin films (hereinafter referred to as PEEK resin films) shown in Table 2, and one type of liquid crystal polymer film (hereinafter referred to as LCP film) shown in Table 2 were prepared respectively.

[0052] The four types of electrolytic copper foils were: electrolytic copper foil 1 with a thickness of 10 μm, TQ-M7-VSP [manufactured by Mitsui Mining & Smelting Co., Ltd.: product name]; electrolytic copper foil 2 with a thickness of 12 μm, CF-T49A-DS-HD2-12 [manufactured by Fukuda Metal Foil & Powder Co., Ltd.: product name]; electrolytic copper foil 3 with a thickness of 18 μm, 3EC-III [manufactured by Mitsui Mining & Smelting Co., Ltd.: product name]; and electrolytic copper foil 4 with a thickness of 10 μm, TQ-VLP [manufactured by Mitsui Mining & Smelting Co., Ltd.: product name].

[0053] · Glossiness of electrolytic copper foil The glossiness of the electrolytic copper foil was measured. This glossiness was measured using a handy gloss meter [manufactured by Horiba, Ltd.: product name Gloss Checker IG-320], in accordance with JIS Z 8741:1997 (equivalent international standards ISO 2813:1994, 7668:1986), under the condition that the incident angle / receiving angle was 60° / 60°.

[0054] · Arithmetic mean height Sa and maximum height Sz of electrolytic copper foil The arithmetic mean height Sa and maximum height Sz of the electrolytic copper foil were measured. These were measured using a laser microscope [manufactured by Olympus Corporation: product name LEXT OLS4100], with the objective lens set at 20 times magnification and the evaluation area set at 646 μm × 648 μm.

[0055] When the glossiness, arithmetic mean height Sa, and maximum height Sz of the shiny (S) surfaces and matte (M) surfaces of these electrolytic copper foils 1 to 4 were measured, the shiny surface of electrolytic copper foil 1, the matte surface of electrolytic copper foil 2, and the shiny surface of electrolytic copper foil 3 met the numerical range of the present invention. In contrast, the matte surface of electrolytic copper foil 1, the shiny surface of electrolytic copper foil 2, the matte surface of electrolytic copper foil 3, and electrolytic copper foil 4 deviated from the numerical range of the present invention.

[0056]

Table 1

[0057] The two types of PEEK resin films, namely PEEK resin films 1 and 2, were both Shin-Etsu SeplaFilm (registered trademark) polyetheretherketone [manufactured by Shin-Etsu Polymer Co., Ltd.: product name]. PEEK resin film 1 was formed into a thin film by a melt extrusion molding method using a molding material containing PEEK resin and talc (weight mixing ratio of PEEK resin: talc = 7:3), and had a thickness of 100 μm. When the properties of this PEEK resin film 1 were measured, the melting point was 339 °C, the relative permittivity was 3.4, the dielectric loss tangent was 0.0048, the linear expansion coefficient was 27 ppm / °C, the crystallinity was 21%, and the storage modulus E' at 340 °C was 3×10 6 Pa.

[0058] PEEK resin film 2 was formed into an alloy film by a melt extrusion molding method using a molding material containing PEEK resin, polyetherimide (PEI) resin, and mica (weight mixing ratio of PEEK resin: PEI resin: mica = 8:2:3), and had a thickness of 100 μm. When the properties of this PEEK resin film 2 were measured, the melting point was 338 °C, the relative permittivity was 3.5, the dielectric loss tangent was 0.0051, the linear expansion coefficient was 28 ppm / °C, the crystallinity was 21%, and the storage modulus E' at 340 °C was 2×10 6 Pa.

[0059] The LCP film was CTF-100 with a thickness of 100 μm [manufactured by Kuraray Co., Ltd.: product name Vectra (registered trademark)]. The properties of this LCP film were that the melting point was 280 °C, the relative permittivity was 3.3, the dielectric loss tangent was 0.002, and the linear expansion coefficient was 18 ppm / °C.

[0060] · Dielectric properties of the film When measuring the dielectric properties (relative permittivity, dielectric loss tangent) as the characteristics of the film, an electronic measuring instrument [manufactured by Anritsu Corporation: product name Compact USB Vector Network Analyzer MS46122B] was used, and the dielectric properties near a frequency of 28 GHz were measured by the Fabry-Perot method, which is a type of open resonator method. The measurement environment was a temperature of 23 ± 2°C and a humidity of 50 ± 10%RH. Also, as the open resonator, a Fabry-Perot resonator Model No. DPS03 [manufactured by Keycom Corporation: product name] was used.

[0061] · Linear expansion coefficient of the film (ppm / °C) When measuring the linear expansion coefficient as a characteristic of the film, a tensile mode using a thermomechanical analyzer [manufactured by Hitachi High-Tech Sciences Corporation: product name SII / SS7100] was used, and it was measured in the range from 10°C to 200°C under the conditions of a load of 50 mN and a heating rate of 5°C / min. The linear expansion coefficient (ppm / °C) was obtained from the slope in the range from 20°C to 140°C. Specifically, the extrusion direction (MD) and the width direction (TD) of the film were measured respectively and their average value was taken.

[0062] · Melting point of the film When measuring the melting point as a characteristic of the film, it was measured in accordance with JIS K 7121. Specifically, about 5 mg of the measurement sample was weighed from the melt-extruded film, and a differential scanning calorimeter [manufactured by SII Technologies Co., Ltd.: product name High-Sensitivity Differential Scanning Calorimeter X-DSC7000] was used, and it was heated in the measurement range from 20°C to 380°C at a heating rate of 10°C / min for measurement.

[0063] · Crystallinity of the PEEK resin film When measuring the crystallinity as a characteristic of the PEEK resin film, about 5 mg of the measurement sample was weighed from the PEEK resin film, and a differential scanning calorimeter [manufactured by SII Technologies Co., Ltd.: product name High-Sensitivity Differential Scanning Calorimeter X-DSC7000] was used and heated at a heating rate of 10°C / min. The crystallinity was calculated using the following formula from the heat quantity (J / g) of the crystal melting peak and the heat quantity (J / g) of the recrystallization peak obtained at this time.

[0064] Degree of crystallinity (%) = {(ΔHm - ΔHc) / ΔHx} × 100 Here, ΔHm is the heat quantity (J / g) of the crystal melting peak under the condition of heating the PEEK resin film at a rate of 10 °C / min, ΔHc is the heat quantity (J / g) of the recrystallization melting peak under the condition of heating the PEEK resin film at a rate of 10 °C / min, and ΔHc is the theoretical value of the melting energy of the 100% crystallized PEEK resin film, which is 130 J / g.

[0065] · Storage elastic modulus E' of the film When measuring the storage elastic modulus E' as a characteristic of the film, the storage elastic modulus E' in the extrusion direction of the film was measured. Specifically, it was cut out to a size of 60 mm in the extrusion direction × 6 mm in the width direction (perpendicular direction to the extrusion direction) of the formed PEEK resin film, and measured under the conditions of a frequency of 1 Hz, a strain of 0.1%, a heating rate of 3 °C / min, and a distance between chucks of 21 mm by a tensile mode using a dynamic viscoelasticity measuring device [manufactured by TA Instruments Japan Co., Ltd.: product name RSA-G2]. The measurement temperature range was set to -60 °C to 360 °C.

[0066]

Table 2

[0067] 〔Example 1〕 Electrolytic copper foil 1, PEEK resin film 1, and electrolytic copper foil 1 were sequentially laminated (see Table 3), and these were set in a hot press machine adjusted to 340 °C and hot-pressed to produce a double-sided copper-clad laminate with a three-layer structure. At this time, the shiny surfaces of the pair of electrolytic copper foils 1 were used as the laminated bonding surfaces, and the PEEK resin film 1 was directly interposed therebetween. Also, the conditions for hot pressing were set with a surface pressure of 4 MPa and a pressing time of 5 minutes.

[0068] After manufacturing a double-sided copper-clad laminate, the adhesion and transmission characteristics of this copper-clad laminate were measured and summarized in Table 4, and the performance of the copper-clad laminate was evaluated as ○ or ×. The adhesion of the copper-clad laminate was measured in accordance with JIS Z 0237:2009. Specifically, the copper-clad laminate was cut to produce a test piece with a width of 25 mm. After fixing this test piece on a support, based on JIS Z 0237:2009, the peel strength was measured while peeling the surface electrolytic copper foil 1 from the test piece under the conditions of a peel rate of 0.3 m / min and a separation angle of 180°, thereby measuring the adhesion.

[0069] Regarding the transmission characteristics of the copper-clad laminate, the electrolytic copper foil was etched to produce a microstrip line with a length of 10 cm and an impedance of 50 Ω, and the transmission characteristics at 30 GHz were measured under the conditions of a temperature of 25 °C and a humidity of 50%. Also, for the ○× evaluation of the performance of the copper-clad laminate, it was set as ○ when it was excellent in practicality and × when it could not withstand practical use.

[0070] 〔Example 2〕 The electrolytic copper foil 2, the PEEK resin film 1, and the electrolytic copper foil 2 were sequentially laminated (see Table 3), and these were set in a hot press machine adjusted to a temperature of 340 °C and hot-pressed to manufacture a double-sided copper-clad laminate with a three-layer structure. At this time, the matte surfaces of the pair of electrolytic copper foils 2 were used as the laminated bonding surfaces, and the PEEK resin film 1 was directly interposed therebetween. Also, the conditions for hot pressing were set with a surface pressure of 4 MPa and a pressing time of 5 minutes. After manufacturing the double-sided copper-clad laminate, similar to Example 1, the adhesion and transmission characteristics of the copper-clad laminate were measured and summarized in Table 4, and the performance of the copper-clad laminate was evaluated as ○ or ×.

[0071] 〔Example 3〕 The electrolytic copper foil 3, the PEEK resin film 1, and the electrolytic copper foil 3 were sequentially laminated (see Table 3), and these were set in a hot press machine adjusted to a temperature of 340 °C and hot-pressed to manufacture a double-sided copper-clad laminate with a three-layer structure. At this time, the shiny surfaces of the pair of electrolytic copper foils 3 were used as the laminated bonding surfaces, and the PEEK resin film 1 was directly interposed therebetween. Also, the conditions for hot pressing were set with a surface pressure of 4 MPa and a pressing time of 5 minutes. When a double-sided copper-clad laminate was fabricated, in the same manner as in Example 1, the adhesion and transmission characteristics of the copper-clad laminate were measured and summarized in Table 4, and the performance of the copper-clad laminate was evaluated as ○×.

[0072] [Example 4] An electrolytic copper foil 1, a PEEK resin film 2, and an electrolytic copper foil 1 were sequentially laminated (see Table 3), and these were set in a hot press machine whose temperature was adjusted to 340 °C and hot-pressed to fabricate a double-sided copper-clad laminate having a three-layer structure. At this time, the shiny surfaces of the pair of electrolytic copper foils 1 were used as the laminated bonding surfaces, and the PEEK resin film 2 was directly interposed therebetween. Also, the conditions for hot pressing were the same as those in Example 1. When a double-sided copper-clad laminate was fabricated, in the same manner as in Example 1, the adhesion and transmission characteristics of the copper-clad laminate were measured and summarized in Table 4, and the performance of the copper-clad laminate was evaluated as ○×.

[0073] [Comparative Example 1] An electrolytic copper foil 1, a PEEK resin film 1, and an electrolytic copper foil 1 were sequentially laminated (see Table 3), and these were set in a hot press machine whose temperature was adjusted to 340 °C and hot-pressed to fabricate a double-sided copper-clad laminate having a three-layer structure. At this time, the matte surfaces of the pair of electrolytic copper foils 1 were used as the laminated bonding surfaces, and the PEEK resin film 1 was directly interposed therebetween. Also, the conditions for hot pressing were set such that the surface pressure was 4 MPa and the pressing time was 5 minutes. When a double-sided copper-clad laminate was fabricated, in the same manner as in Example 1, the adhesion and transmission characteristics of the copper-clad laminate were measured and described in Table 4, and the performance of the copper-clad laminate was evaluated as ○×.

[0074] [Comparative Example 2] An electrolytic copper foil 2, a PEEK resin film 1, and an electrolytic copper foil 2 were sequentially laminated (see Table 3), and these were set in a hot press machine whose temperature was adjusted to 340 °C and hot-pressed to fabricate a double-sided copper-clad laminate having a three-layer structure. At this time, the shiny surfaces of the pair of electrolytic copper foils 2 were used as the laminated bonding surfaces, and the PEEK resin film 1 was directly interposed therebetween. Also, the conditions for hot pressing were set such that the surface pressure was 4 MPa and the pressing time was 5 minutes. When a double-sided copper-clad laminate was fabricated, similar to Example 1, the adhesion and transmission characteristics of the copper-clad laminate were measured and described in Table 4, and the performance of the copper-clad laminate was evaluated as ○×.

[0075] [Comparative Example 3] Electrolytic copper foil 3, PEEK resin film 1, and electrolytic copper foil 3 were sequentially laminated (see Table 3), and these were set in a hot press machine adjusted to 340°C and hot-pressed to fabricate a double-sided copper-clad laminate with a three-layer structure. At this time, the matte surfaces of a pair of electrolytic copper foils 3 were used as the laminated bonding surfaces, and PEEK resin film 1 was directly interposed therebetween. Also, the conditions for hot pressing were set such that the surface pressure was 4 MPa and the pressing time was 5 minutes. When a double-sided copper-clad laminate was fabricated, similar to Example 1, the adhesion and transmission characteristics of the copper-clad laminate were measured and described in Table 4, and the performance of the copper-clad laminate was evaluated as ○×.

[0076] [Comparative Example 4] Electrolytic copper foil 4, PEEK resin film 1, and electrolytic copper foil 4 were sequentially laminated (see Table 3), and these were set in a hot press machine adjusted to 340°C and hot-pressed to fabricate a double-sided copper-clad laminate with a three-layer structure. At this time, the shiny surfaces of a pair of electrolytic copper foils 4 were used as the laminated bonding surfaces, and PEEK resin film 1 was directly interposed therebetween. Also, the conditions for hot pressing were set such that the surface pressure was 4 MPa and the pressing time was 5 minutes. When a double-sided copper-clad laminate was fabricated, similar to Example 1, the adhesion and transmission characteristics of the copper-clad laminate were measured and described in Table 4, and the performance of the copper-clad laminate was evaluated as ○×.

[0077] [Comparative Example 5] Electrolytic copper foil 4, PEEK resin film 1, and electrolytic copper foil 4 were sequentially laminated (see Table 3), and these were set in a hot press machine adjusted to 340°C and hot-pressed to fabricate a double-sided copper-clad laminate with a three-layer structure. At this time, the matte surfaces of a pair of electrolytic copper foils 4 were used as the laminated bonding surfaces, and PEEK resin film 1 was directly interposed therebetween. Also, the conditions for hot pressing were the same as those in Example 1. After manufacturing a double-sided copper-clad laminate, in the same manner as in Example 1, the adhesion and transmission characteristics of the copper-clad laminate were measured and summarized in Table 4, and the performance of the copper-clad laminate was evaluated as ○×.

[0078] [Comparative Example 6] Electrolytic copper foil 1, PEEK resin film 2, and electrolytic copper foil 1 were sequentially laminated (see Table 3), and these were set in a hot press machine adjusted to a temperature of 340 °C and hot-pressed to manufacture a double-sided copper-clad laminate having a three-layer structure. At this time, the matte surfaces of the pair of electrolytic copper foils 1 were used as the laminated bonding surfaces, and the PEEK resin film 1 was directly interposed therebetween. Also, the conditions for hot pressing were the same as in Example 1. After manufacturing a double-sided copper-clad laminate, in the same manner as in Example 1, the adhesion and transmission characteristics of the copper-clad laminate were measured and summarized in Table 4, and the performance of the copper-clad laminate was evaluated as ○×.

[0079] 〔Comparative Example 7〕 Electrolytic copper foil 1, LCP film, and electrolytic copper foil 1 were sequentially laminated (see Table 3), and these were set in a hot press machine and hot-pressed to manufacture a double-sided copper-clad laminate having a three-layer structure. At this time, the shiny surfaces of the pair of electrolytic copper foils 1 were used as the laminated bonding surfaces, and the LCP film was directly interposed therebetween. Also, the temperature for hot pressing was in the temperature range of the melting point of the LCP film - 20 °C or more and +10 °C or less, specifically 270 °C. The conditions for hot pressing were set to a surface pressure of 4 MPa and a pressing time of 5 minutes. After manufacturing a double-sided copper-clad laminate, in the same manner as in Example 1, the adhesion and transmission characteristics of the copper-clad laminate were measured and summarized in Table 4, and the performance of the copper-clad laminate was evaluated as ○×.

[0080] 〔Comparative Example 8〕 Electrolytic copper foil 1, LCP film, and electrolytic copper foil 1 were sequentially laminated (see Table 3), and these were set in a hot press machine adjusted to a temperature of 270 °C and hot-pressed to manufacture a double-sided copper-clad laminate having a three-layer structure. At this time, the matte surfaces of the pair of electrolytic copper foils 1 were used as the laminated bonding surfaces, and the LCP film was directly interposed therebetween. Also, the conditions for hot pressing were the same as in Example 1. After producing a double-sided copper-clad laminate, similar to Example 1, the adhesion and transmission characteristics of the copper-clad laminate were measured and summarized in Table 4, and the performance of the copper-clad laminate was evaluated as ○×.

[0081]

Table 3

[0082]

Table 4

[0083] 〔Evaluation〕 In the case of the copper-clad laminates of each example, it was found that good adhesion and transmission characteristics could be obtained in good balance, and practically excellent effects could be obtained. On the other hand, in the case of the copper-clad laminates of Comparative Examples 1 to 6 and Comparative Example 8, although they were excellent in adhesion, satisfactory transmission characteristics could not be obtained. Further, in the case of the copper-clad laminate of Comparative Example 7, although it was excellent in transmission characteristics, a major problem occurred in adhesion, and doubts were raised about its practicality.

Industrial Applicability

[0084] The laminate and its manufacturing method according to the present invention are used in fields such as copper-clad laminates, flexible printed wiring boards, and high-frequency printed circuits.

Explanation of Signs

[0085] 1 Copper foil 2 Laminated attachment surface 3 Polyether ether ketone resin film 4 Surface to be laminated and attached 5 Copper-clad laminate

Claims

1. A laminate obtained by directly laminating and attaching a copper foil and a polyetheretherketone resin film, wherein the glossiness of the laminated attachment surface of the copper foil to the polyetheretherketone resin film is 30 or more and 90 or less when measured in accordance with the provisions of JIS Z 8741-1997, the arithmetic mean height Sa of the laminated attachment surface of the copper foil to the polyetheretherketone resin film is 0.2 μm or more and 0.4 μm or less, and the maximum height Sz of the laminated attachment surface of the copper foil to the polyetheretherketone resin film is 4 μm or more and 6 μm or less, and a filler is compounded in the polyetheretherketone resin film.

2. The laminate according to claim 1, wherein the relative permittivity of the polyetheretherketone resin film at 28 GHz is 3.7 or less and the dielectric loss tangent is 0.006 or less.

3. The laminate according to claim 1 or 2, wherein the coefficient of linear expansion of the polyetheretherketone resin film is 40 ppm / °C or less.

4. The laminate according to claim 1, 2, or 3, wherein the crystallinity of the polyetheretherketone resin film is 5% or more and 30% or less.

5. The laminate according to any one of claims 1 to 4, wherein the polyetheretherketone resin film is an alloy film with another resin.

6. The laminate according to claim 5, wherein the other resin to be alloyed with the polyetheretherketone resin film is at least one of a polyamideimide resin, a polyphenylene ether resin, a polyetherimide resin, a polyethersulfone resin, a polysulfone resin, a polytetrafluoroethylene resin, and a perfluoroalkoxy resin.

7. The laminate according to any one of claims 1 to 6, wherein the filler is at least one of mica, talc, boron nitride, and silica.

8. A method for manufacturing the laminate according to any one of claims 1 to 7, comprising laminating a polyetheretherketone resin film on the laminated attachment surface of a copper foil, and thermocompression bonding and attaching the copper foil and the polyetheretherketone resin film at a temperature of the melting point of the polyetheretherketone resin film - 20°C or more and +10°C or less.

9. The method for manufacturing a laminate according to claim 8, wherein at least one of the laminated bonding surface of the copper foil and the surface to be laminated of the polyetheretherketone resin film is subjected to corona treatment, plasma treatment, or ultraviolet treatment.

10. The storage elastic modulus during thermocompression bonding of the polyetheretherketone resin film is 5 × 10 ５ Pa or more and 5 × 10 ７ Pa or less. The method for manufacturing a laminate according to claim 8 or 9.

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