Method for manufacturing multilayer printed circuit board

Abstract

The present invention relates to a method for manufacturing a multilayer printed circuit board, the method comprising the steps of: preparing a first circuit board; preparing a metal laminated plate; forming a first multilayer laminated plate by laminating the first circuit board on both surfaces of a carrier film; forming a second multilayer laminated plate by laminating the metal laminated plate on both surfaces of the first multilayer laminated plate, respectively; hot-pressing the second multilayer laminated plate; forming a third multilayer laminated plate by forming a second circuit pattern on the metal foil of the hot-pressed second multilayer laminated plate; and separating the carrier film and the first circuit board from the third multilayer laminated plate, thereby obtaining two multilayer printed circuit boards on which the first circuit board and the second circuit board are laminated. The MFR of the dry film is adjusted to be larger than the MFR of the first thermoplastic resin layer.

Description

Method for manufacturing a multilayer printed circuit board

[0001] The present invention relates to a method for manufacturing a multilayer printed circuit board, and more particularly, to a method for manufacturing a multilayer printed circuit board without a bonding sheet.

[0002] Recently, the high performance of electronic devices requires very high operating speeds and high-frequency communication speeds, and further advanced lightweight and compact design is required to enhance multi-functionality and portability.

[0003] For this reason, printed circuit boards mounted on electronic devices are required to have high-speed, low-loss signal transmission, high-density wiring, thinness, and lightness. Accordingly, substrate materials are also required to have low permittivity, low dielectric constant, thinness, and lightness. To this end, multilayer printed circuit boards using the build-up method have been utilized.

[0004] As a material for the main insulating layer of the multilayer printed circuit board, a thermosetting resin with a high melting point, such as epoxy resin or polyimide resin, is widely used. The insulating layer made of the thermosetting resin can provide good heat resistance and insulation properties to the high-density multilayer printed circuit board. However, in order to stack each circuit board made of the thermosetting resin into multiple layers, a bonding sheet with a lower melting point or curing point than the main insulating layer is required, and additional cutting, welding, and curing processes are required for each bonding sheet. As such, since the manufacturing process and materials increase, the manufacturing cost also increases. In addition, since the thickness of the entire multilayer printed circuit board increases by the thickness of the bonding sheet used in the lamination process, the circuit may be damaged during folding processing, or the spring back characteristic is prominent due to the elasticity of the bonding sheet layer.

[0005] The present invention aims to provide a method for manufacturing a multilayer printed circuit board having excellent interlayer adhesion, low loss characteristics in a high-frequency range, and excellent processability, even without including a bonding sheet.

[0006] To solve the aforementioned problem, the present invention provides a method for manufacturing a multilayer printed circuit board.

[0007] According to an example, a method for manufacturing a multilayer printed circuit board includes the steps of: preparing a first circuit board including a first thermoplastic resin layer and a first circuit pattern disposed on at least one surface of the first thermoplastic resin layer; preparing a metal laminate including a metal foil and a dry film of a thermoplastic resin composition disposed on one surface of the metal foil; laminating the first circuit boards on each side of a carrier film to form a first multilayer laminate; laminating the metal laminates on each side of the first multilayer laminate to form a second multilayer laminate; hot pressing the second multilayer laminate; forming a second circuit pattern on the metal foil of the hot-pressed second multilayer laminate to form a third multilayer laminate; And a step of separating the carrier film and the first circuit board from the third multilayer laminated plate to obtain two multilayer printed circuit boards in which the first circuit board and the second circuit board are laminated, respectively; and the MFR of the dry film is adjusted to be greater than the MFR of the first thermoplastic resin layer.

[0008] According to another example, the method may further include a step of forming a plurality of holes in the second multilayer laminate before or after forming the second circuit pattern; and a step of forming a via by plating the plurality of holes.

[0009] According to another example, the method further comprises the steps of preparing an nth metal laminate comprising an nth metal foil and an nth dry film of a thermoplastic resin composition disposed on one surface of the nth metal foil; and after the step of separating the multilayer printed circuit board, the step of forming the first multilayer laminate or the step of separating the multilayer printed circuit board are repeated one or more times, but the first multilayer laminate is formed using the separated multilayer printed circuit board instead of the first circuit board, and the second multilayer laminate is formed using the nth metal laminate instead of the metal laminate, and the MFR of each dry film can be adjusted to become increasingly larger as it goes from the first thermoplastic resin layer to the nth dry film (n is an integer of 3 or more).

[0010] The method for manufacturing a multilayer printed circuit board according to the present invention, unlike the conventional method, does not involve cutting and bonding bonding sheets, thereby simplifying the manufacturing process and can be applied to a roll-to-roll process using a belt press to manufacture a roll-shaped multilayer printed circuit board. In this case, the manufactured multilayer printed circuit board is built up by directly bonding circuit boards using a single material without a bonding sheet, thereby realizing environmental reliability and low dielectric loss in a high-frequency range.

[0011] In addition, the multilayer printed circuit board manufactured by the present invention can implement a 3D-shaped circuit through bending and folding by making the product slimmer, and thus, processability can be improved.

[0012] In addition, the multilayer printed circuit board manufactured by the present invention has excellent low-loss characteristics in the high-frequency range because each thermoplastic resin layer contains a fluorine-based component.

[0013] FIG. 1 is a cross-sectional view schematically showing a process for manufacturing a multilayer printed circuit board according to an example of the present invention.

[0014] FIG. 2 is a cross-sectional view schematically showing a multilayer printed circuit board manufactured according to an example of the present invention.

[0015] Figure 3 is an enlarged cross-sectional view of part A of Figure 2.

[0016] FIG. 4 is a cross-sectional view schematically showing a multilayer printed circuit board manufactured according to another example of the present invention.

[0017] <Explanation of symbols>

[0018] 110: first circuit board, 111: first thermoplastic resin layer,

[0019] 112: First circuit pattern, 113: Fiber-containing substrate,

[0020] 120a: metal laminate, 121a: first drying film,

[0021] 122a: metal foil, 10: carrier film,

[0022] 20: Protective metal foil, H: Hole,

[0023] Via: via, 100A, 100B: multilayer printed circuit board,

[0024] 120: Second circuit board, 121: Second thermoplastic resin layer,

[0025] 122: Second circuit pattern, Via: via,

[0026] 130: Third circuit board, 131: Third thermoplastic resin layer,

[0027] 132: Third Circuit Pattern

[0028] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. These embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art. The following embodiments may be modified in various ways, and the scope of the present invention is not limited to the following embodiments. Throughout this specification, the same reference numerals denote the same structures.

[0029] Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used in their common sense to those of ordinary skill in the art to which the present invention pertains. Furthermore, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0030] Furthermore, the sizes and thicknesses of each component shown in the drawings are arbitrarily indicated for convenience of explanation, and thus the present invention is not necessarily limited to the illustrated components. In the drawings, the thicknesses are enlarged to clearly represent various layers and regions. Furthermore, in the drawings, the thicknesses of some layers and regions are exaggerated for convenience of explanation.

[0031] Additionally, throughout the specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0032] Additionally, throughout the specification, “above” or “on” means not only when located above or below the target part, but also when there is another part in between, and does not necessarily mean located above with respect to the direction of gravity.

[0033] In addition, the terms “first”, “second”, etc. in this specification are not used to indicate any order or importance, but are used to distinguish between components.

[0034]

[0035] The method for manufacturing a multilayer printed circuit board according to the present invention manufactures a multilayer printed circuit board without using a bonding sheet, and unlike the conventional method, does not perform a cutting and processing process of the bonding sheet. In addition, the present invention can manufacture two multilayer printed circuit boards simultaneously using a carrier film. Therefore, the present invention can simplify the manufacturing process, thereby reducing manufacturing costs and shortening the process time, thereby improving productivity. In addition, the present invention can easily manufacture a roll-type multilayer printed circuit board by applying a roll-to-roll process, particularly a roll-to-roll process using a belt press.

[0036] FIG. 1 is a cross-sectional view schematically showing a process for manufacturing a multilayer printed circuit board according to an example of the present invention.

[0037] According to an example, a method for manufacturing a multilayer printed circuit board according to an example of the present invention comprises the steps of: (S100) preparing a first circuit board (110) including a first thermoplastic resin layer (111) and a first circuit pattern (112) disposed on at least one surface of the first thermoplastic resin layer (111), as illustrated in FIG. 1; (S200) preparing a metal laminate (120a) including a metal foil (122a) and a dry film (121a) of a thermoplastic resin composition disposed on one surface of the metal foil (122a); (S300) forming a first multilayer laminate by laminating the first circuit board (110) on both surfaces of a carrier film (10), respectively; (S400) forming a second multilayer laminate by laminating the metal laminate (120a) on both surfaces of the first multilayer laminate, respectively; (S500) a step of hot pressing the second multilayer laminate; (S600) a step of forming a second circuit pattern on a metal foil (122a) of the hot-pressed second multilayer laminate to form a third multilayer laminate; and (S700) a step of separating the carrier film (10) and the first circuit board (110) from the third multilayer laminate to obtain two multilayer printed circuit boards (100A) in which the first circuit board (110) and the second circuit board (120) are laminated, respectively; and the MFR of the dry film (121a) is adjusted to be greater than the MFR of the first thermoplastic resin layer (111).

[0038] Optionally, a method for manufacturing a multilayer printed circuit board according to an example of the present invention may additionally include, before or after forming the second circuit pattern, (S800) a step of forming a plurality of holes in the second multilayer laminate; and (S900) a step of forming vias by plating the plurality of holes.

[0039] In addition, a method for manufacturing a multilayer printed circuit board according to an example of the present invention further includes a step of preparing an nth metal laminate including an nth metal foil and an nth dry film of an nth thermoplastic resin composition disposed on one surface of the nth metal foil; and after the step of separating the multilayer printed circuit board, the step of forming the first multilayer laminate ['(S300) step'] to the step of separating the multilayer printed circuit board ['(S700) step'] are repeated once or a plurality of times, but the first multilayer laminate is formed using the separated multilayer printed circuit board (100A) instead of the first circuit board (110), and the second multilayer laminate is formed using the n-1th metal laminate (not shown) instead of the metal laminate (120a), and the MFR of each dry film is gradually adjusted to become larger as it goes from the first thermoplastic resin layer to the nth dry film, and n is 3 or more. It can be an integer.

[0040] However, the above steps are not limited to the above, and the manufacturing process does not have to be performed sequentially by performing each step below. Rather, the steps of each process can be modified or selectively mixed and performed according to the design specifications. In particular, there is no temporal relationship between steps (S100) and (S200).

[0041] Hereinafter, with reference to FIG. 1, each step of a method for manufacturing a multilayer printed circuit board using a roll-to-roll device according to an example of the present invention will be described.

[0042] (S100) Step: Preparation of the first circuit board

[0043] A first circuit board (110) including a first thermoplastic resin layer (111) and a first circuit pattern (112) arranged on at least one surface of the first thermoplastic resin layer (111) is prepared.

[0044] The first circuit board (110) used in the present invention may be of panel type or roll type. For example, the first circuit board (110) may be of roll type, specifically, a roll-type double-sided circuit board, or more specifically, a roll-type double-sided flexible circuit board.

[0045] According to an example, the first circuit board (110) includes a first thermoplastic resin layer (111) and a first circuit pattern (112) respectively disposed on both sides of the first thermoplastic resin layer (111), as illustrated in FIG. 1. Optionally, the first circuit board (110) may additionally include a fiber-containing substrate (113) embedded in the first thermoplastic resin layer (111).

[0046] Below, each component of the first circuit board (110) is described.

[0047] (1) First thermoplastic resin layer

[0048] The above first thermoplastic resin layer (111) is an insulating layer, and can be directly bonded to the dry film (121a) to build up circuit boards while protecting the first circuit pattern (112). It is preferable that the first thermoplastic resin layer (111) be a completely solidified insulating layer to ensure dimensional stability of the first circuit pattern (112) when laminating the second circuit board (120) on the first circuit board (110).

[0049] The melt flow rate (MFR) of the first thermoplastic resin layer (111) is smaller than the MFR of the second thermoplastic resin layer (121), as described above. In one example, the MFR of the dry film (121a) may be 10 to 100 times larger than the MFR of the first thermoplastic resin layer (121). The MFR of the first thermoplastic resin layer (111) may be in the range of about 0 to 1 g / 10 min, specifically about 0.01 to 1 g / 10 min, at a temperature of 372° C. and a load of 5 kg, and the MFR of the dry film (121a) may be more than 1.5 g / 10 min and less than or equal to 5 g / 10 min, at a temperature of 372° C. and a load of 5 kg. Here, the MFR (Melt Flow Rate) of the resin layer and dry film is the total amount of extruded resin measured for 10 min under the conditions of 372 ℃ and 5 kg according to the ISO 12086-2 test method.

[0050] The dielectric constant (Dk) of the first thermoplastic resin layer (111) may be about 2 to 7 at 25°C and 10 GHz, and the dielectric loss tangent (Df) may be 0.0001 to 0.002.

[0051] The first thermoplastic resin layer (111) may include a thermoplastic component commonly known in the art. For example, the first thermoplastic resin layer (111) may be formed of a first thermoplastic resin composition (C1) including a first fluororesin filler, a first inorganic filler, and a first binder resin. Optionally, the first thermoplastic resin composition (C1) may additionally include a first organic solvent.

[0052] Hereinafter, the composition of the first thermoplastic resin composition (C1) will be described.

[0053] 1) First fluorine resin filler

[0054] In the first thermoplastic resin composition (C1) according to the present invention, the first fluororesin filler is a fluororesin particle containing fluorine (F), and is a particle-shaped organic filler such as a powder in a solid state at room temperature (about 20±5°C). The first fluororesin filler maintains the particle shape when the first thermoplastic resin composition (C1) is dried, and is bound together with the first inorganic filler by the first binder resin, and is subsequently melted by high-temperature pressing and included in the first thermoplastic resin layer (111) as a polymer matrix component together with the first binder resin. Therefore, the first fluororesin filler not only implements low dielectric constant and low dielectric loss characteristics of the first thermoplastic resin layer, but also can improve heat resistance and improve adhesion between a fiber-containing substrate or a metal foil.

[0055] The first fluororesin filler usable in the present invention is not particularly limited as long as it is a particle formed of a fluorine-containing resin in the art. Non-limiting examples of the first fluororesin filler include polytetrafluoroethylene (PTFE), perfluoroalkoxy alkane (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polychlorotrifluoroethylene (PCTFE), ethylene-tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-chlorotrifluoroethylene copolymer (TFE / CTFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), polychlorotrifluoroethylene (PCTFE), etc., and these may be used alone or in a mixture of two or more. For example, the first fluororesin filler may include two or more selected from the group consisting of PFA, PTFE, and FEP.

[0056] The melt flow rate (MFR) of the first fluororesin filler may vary depending on the type or molecular weight of the filler, or the mixing ratio of two or more fillers. For example, the MFR of PTFE may be 0 to 0.1 g / 10 min (specifically, about 0.01 to 1 g / 10 min), the MFR of PFA may be about 0.1 to 20 g / 10 min, and the MFR of FEP may be about 1 to 40 g / min. As such, the MFR of the first fluororesin filler may be in the range of about 0.01 to 40 g / 10 min at a temperature of 372° C. and a load of 5 kg. At this time, the MFR of the first fluororesin filler is preferably smaller than the MFR of the second fluororesin filler of the second thermoplastic resin composition. Accordingly, the first thermoplastic resin layer (111) has superior dimensional stability and flow stability compared to the dry film (121a) at the same temperature, thereby improving the dimensional stability of the first circuit pattern (112). Here, the MFR (Melt Flow Rate) of the first fluororesin is measured by measuring the total amount of extruded resin for 10 minutes under the conditions of 372°C and 5 kg according to the ISO 12086-2 test method. If the first fluororesin is a mixture of two or more types, the MFR of the mixture is measured.

[0057] In the present invention, the first fluororesin filler includes two or more types of fluororesin fillers having different MFRs, and by controlling the mixing ratio thereof, the MFR of the first thermoplastic resin layer (111) can be controlled within a range of about 0 to 0.1 g / 10 min, specifically, about 0.01 to 1 g / 10 min. For example, the first fluororesin filler may include a 1A fluororesin filler having an MFR of about 0.01 to 10 g / 10 min at a temperature of 372° C. and a load of 5 kg; and a 1B fluororesin filler having an MFR of about 0.1 to 40 g / 10 min. At this time, the content of the 1A fluororesin filler may be greater than the content of the 1B fluororesin filler.

[0058] For example, the first fluororesin filler includes at least one selected from the group consisting of (a) PTFE and (b) PFA and FEP, wherein the content of the PTFE may be greater than the content of the PFA and / or FEP. The usage ratio of the PTFE and the PFA and / or FEP (PTFE: PFA and / or FEP) may be a weight ratio of 2:1 to 10:1. In addition, when PTFE is used together with PFA and FEP as the first fluororesin filler, the content of the PFA may be adjusted to be greater than the content of the FEP so that the MFR of the first thermoplastic resin layer (111) becomes smaller than the MFR of the second thermoplastic resin layer (121). Here, PFA and / or FEP means PFA, or FEP, or a mixture of PFA and FEP.

[0059] As another example, the first fluororesin filler includes (a) PTFE; and (b) PFA, wherein the content of PTFE may be greater than the content of PFA. The usage ratio of PTFE and PFA (PTFE:PFA) may be 2:1 to 10:1 by weight.

[0060] As another example, the first fluororesin filler may include a fluororesin filler with a low MFR, such as PTFE. In this case, the second fluororesin may include a fluororesin filler with a higher MFR than PTFE, such as PFA, PTFE, or both. Furthermore, the second fluororesin may additionally include PTFE, in which case the content of PTFE in the second fluororesin is lower than the content of PTFE in the first fluororesin filler.

[0061] In addition, the average particle diameter (D50) of the first fluororesin filler may be in the range of about 5 to 30 μm. If the first fluororesin filler has the above-described average particle diameter, the first fluororesin filler can be uniformly dispersed without agglomeration in the first thermoplastic resin composition (C1), and the handling property of the first thermoplastic resin composition (C1) after coating can be improved. At this time, in the present invention, as the first fluororesin filler, one type of fluororesin filler having the same average particle diameter can be used alone, or two or more types of fluororesin fillers having different average particle diameters can be used in combination. Here, the average particle diameter (D50) of the first fluororesin filler can be measured according to the ASTM D4464-10 test method.

[0062] According to an example, the first fluororesin filler may include a first A fluororesin filler having an average particle diameter (D50) of 20 to 30 μm; and a first B fluororesin filler having an average particle diameter (D50) of 5 to 10 μm.

[0063] In addition, the first fluororesin filler can have a relative permittivity (Dk) of about 2.0 to 2.1 and a dielectric loss tangent (Df) of 0.0001 to 0.002 at 25°C and 10 GHz. In this way, since the first fluororesin filler has low dielectric properties, the low permittivity and low dielectric loss properties of the first thermoplastic resin layer (111) can be implemented. Here, the relative permittivity (Dk) and the dielectric loss tangent (Df) of the first fluororesin filler are measured under the conditions of 25°C and 10 GHz according to the split post dielectric resonator (SPDR) method (IEC 61189-2-721 test method).

[0064] In addition, the shape of the first fluororesin filler is not particularly limited, and includes, for example, spherical, flake, dendrite, conical, pyramidal, and amorphous shapes, and these may be used alone or in combination of two or more. In one example, the shape of the first fluororesin filler may be spherical. In this case, since the surface area of ​​the first fluororesin filler is minimized, the processing characteristics of the first thermoplastic resin composition can be improved, and isotropic characteristics can be imparted to the first thermoplastic resin layer.

[0065] In the first thermoplastic resin composition (C1) of the present invention, the content of the first fluororesin filler may be in the range of about 50 to 80 wt% based on the total weight of the resin composition. By adjusting the content of the first fluororesin filler within the above-described range, the resin composition can form a resin layer having a low dielectric constant.

[0066] For example, when the first fluororesin filler includes PTFE and PFA in a weight ratio of 10:1, and the content of the first fluororesin filler is adjusted to about 50 wt%, the content of the first inorganic filler is adjusted to about 45 wt%, and the content of the first binder resin is adjusted to about 5 wt%, the MFR of the first thermoplastic resin layer may be 0 g / 10 min.

[0067] As another example, when the first fluororesin filler includes PTFE and PFA in a weight ratio of 2:1, and the content of the first fluororesin filler is adjusted to about 80 wt%, the content of the first inorganic filler is adjusted to about 17 wt%, and the content of the first binder resin is adjusted to about 3 wt%, the MFR of the first thermoplastic resin layer may be about 1 g / 10 min.

[0068] 2) 1st weapon filler

[0069] In the first thermoplastic resin composition (C1) according to the present invention, the first inorganic filler can reduce the difference in coefficient of thermal expansion (CTE) between the first thermoplastic resin layer (111) and other layers [e.g., the first circuit pattern (112), the fiber-containing substrate (113)], thereby improving the bending characteristics, low expansion, mechanical strength (toughness), and low stress of the first circuit board (110). In addition, the dielectric characteristics of the first thermoplastic resin layer (111) can be controlled depending on the components and / or content of the first inorganic filler.

[0070] Non-limiting examples of the first inorganic filler usable in the present invention include silica such as natural silica, fused silica, amorphous silica, crystalline silica, etc.; boehmite, alumina, talc, glass (e.g., spherical glass), calcium carbonate, magnesium carbonate, magnesia, clay, calcium silicate, titanium oxide, antimony oxide, glass fiber, aluminum borate, barium titanate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titania (e.g., TiO2), barium zirconate, calcium zirconate, boron nitride, silicon nitride, talc, mica, etc. These first inorganic fillers may be used alone or in combination of two or more. Among these, since silica, alumina, and titania have low dielectric constants, they can lower the permittivity and dielectric loss tangent of the resin layer while reducing the difference in thermal expansion coefficient between the resin layer and the metal foil.

[0071] In one example, the first inorganic filler may include at least one selected from the group consisting of silica (e.g., SiO2), alumina (e.g., Al2O3), and titania (e.g., TiO2). In another example, the first inorganic filler may be titania (e.g., TiO2); and silica (e.g., SiO2). In this case, titania may be included in a larger amount than silica. For example, the content of titania may be about 20 to 30 wt% based on the total amount of the resin composition.

[0072] The size (e.g., average particle diameter, maximum particle diameter), shape and content of these first inorganic fillers are important parameters that affect the properties of the first thermoplastic resin layer.

[0073] Specifically, the average particle diameter (D50) of the first inorganic filler may be in the range of approximately 0.1 to 30 μm. This is advantageous for the dispersibility of the first inorganic filler. In this case, the first inorganic filler may include two or more types of inorganic fillers having different maximum particle diameters.

[0074] In one example, the first inorganic filler may include a first A inorganic filler having an average particle diameter (D50) of about 0.1 to 10 μm; and a first B inorganic filler having an average particle diameter (D50) of greater than about 10 μm and less than or equal to about 30 μm. In this case, the first A inorganic filler may include two or more types of inorganic fillers having different components, and the first B inorganic filler may also include two or more types of inorganic fillers having different components. For example, the first inorganic filler may include a first A inorganic filler having an average particle diameter (D50) of about 0.1 to 10 μm; and a first B inorganic filler having an average particle diameter (D50) of greater than about 10 μm and less than or equal to about 30 μm, and the first A inorganic filler may include silica and titania, and the first B inorganic filler may include silica and titania. Here, the average particle diameter (D50) of the first weapon filler can be measured according to ASTM D4464-10.

[0075] In addition, the shape of the first weapon filler is not particularly limited, and includes, for example, a sphere, a flake, a dendrite, a cone, a pyramid, an amorphous shape, etc.

[0076] Additionally, the first inorganic filler may be surface-treated with a surface treatment agent. The surface treatment agent is not particularly limited as long as it is generally known in the art, and examples thereof include a silane coupling agent. In this case, the content of the silane coupling agent may be about 0.1 to 20 parts by weight, specifically about 0.1 to 10 parts by weight, based on 100 parts by weight of the first inorganic filler.

[0077] The silane coupling agent usable in the present invention is not particularly limited as long as it is one commonly known in the art, and examples thereof include vinyl-based, epoxy-based, methacryloxy-based, amino-based, mercapto-sulfide-based, and ureide-based silane coupling agents, and may be used alone or in combination of two or more. Such silane coupling agents can improve the adhesion between the first inorganic filler and other components during solidification of the resin composition.

[0078] The aforementioned silane coupling agent not only serves to surface-treat the first inorganic filler, but may also be additionally added as a component of the first thermoplastic resin composition (C1). In this case, the dispersibility of the first inorganic filler is improved by the silane coupling agent, thereby improving the low-dielectric properties of the first thermoplastic resin layer.

[0079] The content of such silane coupling agent may be about 0.0001 to 10 wt%, specifically about 0.01 to 5 wt%, and more specifically about 0.1 to 3 wt%, based on the total amount of the resin composition.

[0080] In the resin composition of the present invention, the content of the first inorganic filler may be in the range of about 20 to 50 wt%, specifically about 30 to 45 wt%, based on the total weight of the resin composition. If the content of the first inorganic filler is less than about 20 wt%, the mechanical strength increasing effect may be insufficient, making process application difficult. On the other hand, if the content of the first inorganic filler exceeds about 50 wt%, the moldability of the resin composition may deteriorate.

[0081] 3) First binder resin

[0082] In the first thermoplastic resin composition (C1) of the present invention, the first binder resin is a binder resin having excellent high-temperature heat resistance, and can bind the first fluororesin filler and the first inorganic filler when forming the first thermoplastic resin layer. In addition, the first binder resin has excellent adhesion (adhesion) to a metal foil, and thus can improve the adhesive properties between the dried product of the first thermoplastic resin composition (C1) and the metal foil.

[0083] Such first binder resin may have a thermal decomposition temperature (Td) of about 400°C or higher, specifically in the range of about 400 to 450°C.

[0084] In addition, the first binder resin may have a dielectric constant (Df) of about 0.0001 to 0.002 at 10 GHz and a dielectric constant (Dk) of about 2.0 to 3.0 at 10 Hz. In this case, the low-k dielectric properties of the first thermoplastic resin layer (111) can be improved. Here, the dielectric constant (Dk) and dielectric constant (Df) of the first binder resin are measured under conditions of 25°C and 10 GHz according to the split post dielectric resonator (SPDR) method (IEC 61189-2-721 test method).

[0085] In addition, the viscosity (at about 25°C) of a solution in which 5 wt% of the first binder resin is dissolved in an organic solvent (e.g., toluene) may be about 50 to 100 cPs. In this case, the viscosity of the first thermoplastic resin composition (C1) of the present invention may be adjusted to be within a range of about 150 to 500 cPs, so that processability may be improved when manufacturing a roll-type first circuit board. Here, the viscosity of the first binder resin and the resin composition are each measured using a viscosity measurement method known in the art, such as the Blook field method (rotation speed: about 20 rpm).

[0086] In one example, the first binder resin may be a fluorinated elastomer.

[0087] The above fluorine-based elastomer is a thermoplastic elastomer containing at least one fluorine (F) atom in at least one repeating unit, and unlike the first fluorine resin filler, is soluble in an organic solvent. This fluorine-based elastomer has a high thermal decomposition temperature (Td) of 400°C or higher, and a low dielectric constant (Df) and dielectric constant (Dk).

[0088] Fluorine-based elastomers usable in the present invention include fluoroelastomers (FKM), specifically copolymers containing two or more of vinylidene fluoride (VDF), hexafluoropropylene (HFP), and tetrafluoroethylene (TFE). Depending on the number of monomers, they may be binary or ternary copolymers, and examples thereof include, but are not limited to, VDF-HFP copolymers and VDF-HFP-TFE copolymers. These may be used alone, or two or more may be mixed and used.

[0089] The content of fluorine (F) in the fluorine-based elastomer is not particularly limited, but when it is within the range of about 65 to 80 wt% per molecule of the fluorine-based elastomer, excellent low-dielectric properties and low-dielectric loss properties can be imparted to the first thermoplastic resin layer (111).

[0090] In the first thermoplastic resin composition (C1), the content of the first binder resin may be in a range of about 1 to 10 wt%, specifically about 1 to 7 wt%, and more specifically about 1 to 5 wt%, based on the total amount (100 wt%) of the first thermoplastic resin composition (excluding the organic solvent and additives). If the content of the first binder resin is less than about 1 wt%, the effect of binding the fillers may be reduced, and on the other hand, if the content of the first binder resin exceeds 10 wt%, not only the adhesion with the fiber-containing substrate (113) but also the adhesion with a metal foil (e.g., copper foil) may be reduced, and thus the metal foil (circuit pattern) may be peeled off when manufacturing and using a roll-type first circuit board.

[0091] 4) First organic solvent

[0092] The first thermoplastic resin composition (C1) of the present invention may additionally include a first organic solvent.

[0093] The first organic solvent usable in the present invention is not particularly limited as long as it can dissolve the first binder resin. Examples of such first organic solvents include, but are not limited to, aromatic compounds such as toluene, xylene, and ethylbenzene; alcohol compounds such as methanol, ethanol, butanol, and isobutanol; ketone compounds such as acetone, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, isophorone, and N-methylpyrrolidone; and ester compounds such as ethyl acetate, butyl acetate, and methyl cellosolve acetate. These may be used alone, or two or more may be mixed and used.

[0094] The content of the first organic solvent may be used as a content known in the art, and may be a residual amount adjusted so that the total amount of the first thermoplastic resin composition (C1) becomes 100 wt%. For example, it may be in the range of about 40 to 70 parts by weight, specifically in the range of about 45 to 65 parts by weight, based on 100 parts by weight of the first thermoplastic resin composition (C1) (excluding the first organic solvent and the first additive).

[0095] 5) First additive

[0096] Meanwhile, the first thermoplastic resin composition (C1) of the present invention may further include, in addition to the first fluororesin filler, the first inorganic filler, the first binder resin, and the first organic solvent described above, a first additive such as a flame retardant, another thermosetting resin or thermoplastic resin, an ultraviolet absorber, an antioxidant, a polymerization initiator, a dye, a pigment, a dispersant, a thickener, a leveling agent, a colorant, etc. known in the art, as needed, within a range that does not impair the physical properties of the composition.

[0097] The content of the first additive can be used as known in the art, and may be, for example, about 0.0001 to 10 wt% based on the total amount of the first thermoplastic resin composition (C1).

[0098] The viscosity of the first thermoplastic resin composition (C1) according to the present invention can be adjusted depending on the types and contents of the first fluororesin filler, the first inorganic filler, the first binder resin, and the first organic solvent in the composition, and can be, for example, about 200 to 1000 cPs. In one example, when the first thermoplastic resin composition (C1) has the viscosity described above, the first thermoplastic resin layer (111) can be directly formed on the metal foil by directly applying the first thermoplastic resin composition (C1) on the metal foil using a roll-to-roll coating method and drying the result.

[0099] (b) First circuit pattern

[0100] In the first circuit board (110) according to the present invention, the first circuit pattern (112) is arranged on both sides of the first thermoplastic resin layer (111) described above, and is patterned in a predetermined shape with a predetermined width and thickness. This first circuit pattern (112) can perform various functions depending on the design of the corresponding layer, and can be, for example, a power supply line, a ground line, a ground electrode, etc. In this way, some of the first circuit patterns (112) arranged on each side of the first thermoplastic resin layer (111) can be electrically connected to each other, or can be electrically connected to a circuit pattern in another board [e.g., a second circuit pattern (122), etc.] through a via.

[0101] The material forming the first circuit pattern (112) is not particularly limited as long as it is a conductive material commonly used in the art, specifically a conductive metal. Non-limiting examples of the conductive material include chromium (Cr), nickel (Ni), zinc (Zn), molybdenum (Mo), tungsten (W), cobalt (Co), lead (Pb), silver (Ag), tantalum (Ta), copper (Cu), aluminum (Al), manganese (Mn), iron (Fe), titanium (Ti), tin (Sn), steel, zinc (Zn), vanadium (V), palladium (Pd), etc., and these may be used alone or in the form of a mixture or alloy of two or more. In one example, the material of the first circuit pattern (112) may be copper (Cu).

[0102] (c) fiber-containing substrate

[0103] The first circuit board (110) according to the present invention may additionally include a fiber-containing substrate (113).

[0104] For example, as illustrated in FIG. 3, a fiber-containing substrate (113) embedded in the first thermoplastic resin layer (111) may be additionally included.

[0105] As another example, although not shown, a fiber-containing substrate (113) may additionally be included between the first thermoplastic resin layers (111).

[0106] The fiber-containing substrate (113) is a portion that supports the first circuit board (110), and since it contains fibers, it can improve the low dielectric constant and low loss characteristics of the first circuit board (110). In addition, the fiber-containing substrate (113) can be in close contact with the dried product of the first thermoplastic resin during the manufacture of the first circuit board, thereby exhibiting excellent flexibility, heat resistance, and adhesiveness.

[0107] For example, the fiber-containing substrate (113) may be a fiber aggregate.

[0108] As another example, the fiber-containing substrate (113) may be a prepreg comprising a fiber assembly; and a semi-cured resin impregnated into the fiber assembly and having a thermal decomposition temperature of 450°C or higher. Here, the semi-cured resin is a resin in a B-stage state that is semi-cured by impregnating a high heat-resistant resin composition having a thermal decomposition temperature of 450°C or higher into the fiber assembly and then heating it.

[0109] The above fiber aggregate may be a plurality of fibers, or a fiber-containing substrate made of fibers such as yarn, woven fabric, non-woven fabric, knitting, braid, etc.

[0110] Non-limiting examples of the above fibers include vegetable fibers such as cotton and hemp; animal fibers such as wool and silk; regenerated fibers such as rayon; synthetic fibers such as polyester, acrylic, nylon, polyurethane, etc.; inorganic fibers such as glass fiber and carbon fiber; and metal fibers, which may be used alone or in combination of two or more. Among these, inorganic fibers such as glass fiber and carbon fiber have low moisture content, so pores are not formed in the fiber-containing substrate (113) during hot pressing later, and they also have excellent thermal stability.

[0111] Examples of the above fiber assembly include, but are not limited to, a plurality of glass fibers (e.g., E-glass, D-glass, S-glass, NE-glass, T-glass, and Q-glass, etc.), glass paper, glass roving, glass yarn, glass woven fabric, glass chopped strands, glass chopped strands mat, glass roving cloth, glass surfacing mat, etc.

[0112] The semi-cured resin usable in the present invention is a cured product obtained by semi-curing (B-stage) a high heat-resistant resin composition having a thermal decomposition temperature of 400°C or higher. The high heat-resistant resin composition usable in the present invention is not particularly limited as long as it is one commonly used in prepregs in the art and has a thermal decomposition temperature of 400°C or higher.

[0113] According to an example, the high heat resistance resin composition may include at least one high heat resistance resin selected from the group consisting of epoxy resins and fluororesins, and may optionally further include a curing agent.

[0114] In the above-described high heat-resistant resin composition, the epoxy resin is a thermosetting resin, and by forming a three-dimensional network structure after curing, it can improve the adhesive strength between the prepreg (113) and the first thermoplastic resin layer (111), and also has excellent heat resistance, water resistance, and moisture resistance, thereby improving the heat-resistant reliability of the first circuit board. In addition, the epoxy resin not only has excellent mechanical strength, electrical insulation, chemical resistance, dimensional stability, and moldability, but also has excellent compatibility with other resins.

[0115] The epoxy resin usable in the present invention is a polymer containing at least one epoxide group in the molecule, and is preferably an epoxy resin that does not contain a halogen atom such as bromine in the molecule. In addition, the epoxy resin may contain silicone, urethane, polyimide, polyamide, etc. in the molecule, and may also contain phosphorus atoms, sulfur atoms, nitrogen atoms, etc. in the molecule.

[0116] Non-limiting examples of such epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, or hydrogenated versions thereof, glycidyl ether epoxy resins such as phenol novolac type epoxy resin, cresol novolac type epoxy resin, glycidyl ester epoxy resins such as hexahydrophthalic acid glycidyl ester, dimer acid glycidyl ester, glycidylamine epoxy resins such as triglycidyl isocyanurate, tetraglycidyldiamino diphenylmethane, linear aliphatic epoxy resins such as epoxidized polybutadiene, and epoxidized soybean oil, etc. These may be used alone or in combination of two or more.

[0117] In the above-described high heat-resistant resin composition, the fluoropolymer is a thermoplastic resin with excellent chemical stability and high-temperature heat stability, and is a type of heat-resistant resin with a high melting point (Tm) of about 260 ℃ or higher, and is preferably in a liquid state. Examples of such fluoropolymers include, but are not limited to, polytetrafluoroethylene resin (PTFE), perfluoroalkoxy alkane (PFA), tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP), polychlorotrifluoroethylene resin (PCTFE), ethylene-tetrafluoroethylene copolymer resin (ETFE), ethylene-chlorotrifluoroethylene copolymer resin (ECTFE), tetrafluoroethylene-chlorotrifluoroethylene copolymer (TFE / CTFE), polyvinylidene fluoride resin (PVDF), polyvinyl fluoride resin (PVF), tetrafluoroethylene-perfluoroalkyl vinyl ether-hexafluoropropylene copolymer resin, and the like.

[0118] In the above high heat-resistant resin composition, the curing agent is a component that cures the epoxy resin, and is not particularly limited as long as it is known in the art to cure the epoxy resin, and examples thereof include an acid anhydride-based curing agent, an amine-based curing agent, a phenol-based curing agent, and the like.

[0119] Specifically, examples of the curing agent include acid anhydride curing agents such as tetrahydrophthalic anhydride, methyl tetrahydrophthalic anhydride, methyl hexahydrophthalic anhydride, hexahydrophthalic anhydride, trialkyl tetrahydrophthalic anhydride, methyl cyclohexenedicarboxylic anhydride, phthalic anhydride, maleic anhydride, and pyromellitic anhydride; aromatic amine curing agents such as metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone; aliphatic amine curing agents such as diethylenetriamine and triethylenetetramine; Phenolic curing agents such as phenol aralkyl type phenol resin, phenol novolac type phenol resin, xyloc type phenol resin, cresol novolac type phenol resin, naphthol type phenol resin, terpene type phenol resin, multifunctional type phenol resin, dicyclopentadiene type phenol resin, naphthalene type phenol resin, novolac type phenol resin synthesized from bisphenol A and resol; latent curing agents such as dicyandiamide, etc., are not limited thereto. These may be used alone or in a mixture of two or more.

[0120] The content of such a hardener is not particularly limited, and may be, for example, about 1 to 10 parts by weight, specifically about 1 to 6 parts by weight, based on 100 parts by weight of a high heat-resistant resin (e.g., epoxy resin).

[0121] The thickness of the aforementioned fiber-containing substrate (113) is not particularly limited and may be, for example, about 10 to 200 μm. However, when the thickness of the fiber-containing substrate (113) is in the range of about 30 to 70% of the thickness of the flexible metal laminate, the thermal and mechanical properties of the first circuit board can be further improved.

[0122] The first circuit board (110) described above can be manufactured through various methods known in the art.

[0123] For example, it can be manufactured by continuously supplying a roll-type metal laminate using a roll-to-roll device, opening a hole in the metal laminate to perform through-hole plating, and then etching a metal foil (e.g., copper foil) including a plating film to form a circuit.

[0124] The above metal laminate (hereinafter, “first metal laminate”) includes a first thermoplastic resin layer; and metal foils disposed on each of both sides of the first thermoplastic resin layer, and may be of roll type.

[0125] These roll type first metal laminates can be manufactured by various methods known in the art.

[0126] For example, a roll-type first metal laminate may include a step of continuously forming a roll-type first unit member including a dry film (hereinafter, "1A dry film") of the 1A metal foil and the 1A thermoplastic resin composition by applying a 1A thermoplastic resin composition on one surface of a continuously supplied first metal foil and drying it; a step of continuously forming a roll-type second unit member including a 1B metal foil and a dry film (hereinafter, "1B dry film") of the 1B thermoplastic resin composition by applying a 1B thermoplastic resin composition on one surface of a continuously supplied 1B metal foil and drying it; and a step of stacking a second unit member on the first unit member such that the dry films of the respective unit members are in contact with each other, and then heating and pressurizing. Optionally, a fiber-containing substrate may be disposed between the dry films.

[0127] The first and second unit members are roll-type members in which each resin composition is directly applied (coated) onto one surface of a metal foil, and then dried, so that a dry film in which the solvent is removed from the applied resin composition is formed on one surface of each metal foil. These first and second unit members can be manufactured by directly coating and drying each resin composition onto each metal foil, without a film forming process and a high-temperature firing process. At this time, since the dry films have excellent adhesion to the metal foil, the durability of the metal laminate can be improved.

[0128] The above 1A thermoplastic resin composition comprises a 1A fluororesin filler, a 1A inorganic filler, and a 1A binder resin, and may optionally comprise a 1A organic solvent.

[0129] The above 1B thermoplastic resin composition is the same as or different from the 1A thermoplastic resin composition, and includes a 1B fluorine resin filler, a 1B inorganic filler, and a 1B binder resin, and may optionally include a 1B organic solvent.

[0130] Descriptions of the respective components of these first A and first B thermoplastic resin compositions are omitted because they are the same as those described for the first thermoplastic resin composition (C1).

[0131] The above-mentioned metal foils 1A and 1B can be used without any particular limitation as long as they are conventional metal components applied to metal laminates or printed circuit boards in the relevant field. For example, each metal foil can be a metal thin film selected from the group consisting of copper (Cu), iron (Fe), nickel (Ni), titanium (Ti), aluminum (Al), silver (Ag), and gold (Au), or an alloy thin film of two or more types. Preferably, the first metal foil (13A) can be a copper foil having excellent electrical conductivity and low price. In this case, the copper foil can be any conventional copper foil known in the relevant field without limitation, and any copper foil manufactured by a rolling method or an electrolytic method can be used.

[0132] The surface roughness of the above 1A and 1B metal foils is not particularly limited, and may be, for example, about 0.5 to 3 ㎛ each.

[0133] In addition, the thickness of the first A and first B metal foils is not particularly limited, and may be in the range of about 1 to 50 μm, specifically, in the range of about 1 to 30 μm, taking into account the thickness and mechanical properties of the metal laminate.

[0134] The above direct application (coating) method is not particularly limited, and includes, for example, roll-to-roll coating, and specifically, comma coating, slot die coating, curtain coating, and spray coating.

[0135] The drying process of the above-mentioned 1A and 1B resin compositions is to dry the 1A and 1B thermoplastic resin compositions, and particularly to remove the organic solvent within the compositions. This drying process can be performed at a temperature of about 100 to 180°C for about 3 to 30 minutes. As a result, a dry film of the resin composition can be formed on each metal foil. In this way, the present invention only dries each resin composition prior to the heating and pressurizing process of the first and second unit members, and does not perform a high-temperature firing process of 350°C or higher.

[0136] The first and second unit members obtained as described above are laminated, and then heated and pressed. However, the laminate is performed so that the dry films of each unit member are in contact with each other. Optionally, a fiber-containing substrate may be placed between the dry films.

[0137] For example, the first and second unit members can be laminated on both sides of a fiber-containing substrate continuously supplied from a fiber-containing substrate supply roller, and then these can be thermally bonded at 300 to 340°C. At this time, the unit members are continuously supplied and laminated and thermally bonded so that the dry film of each unit member is in contact with the fiber-containing substrate.

[0138] The description of the fiber-containing substrate is omitted because it is the same as that described in the first embodiment section.

[0139] In the above thermocompression bonding, a hot press device, a pair of pressurized heating rollers, or a belt press can be used. At this time, each unit member can be heated and pressed at a pressure (e.g., linear pressure) of about 10 to 50 kgf / ㎤ per 1 m and a temperature of about 250 to 400 ℃ for about 1 to 2 hours. Through this thermocompression bonding process, each dry film is (completely) solidified, thereby obtaining a first metal laminate including a first A metal foil / first thermoplastic resin layer / first B metal foil, and optionally further including a fiber-containing substrate disposed within the first thermoplastic resin layer. At this time, the first thermoplastic resin layer is a cured film with minimized internal pores and is an insulating layer in a stabilized state.

[0140] The first metal laminate of the roll type manufactured as described above can be manufactured into a first circuit board (110) through a hole processing process, a hole plating process, a circuit pattern forming process, etc., which are commonly known in the art. For example, a plurality of holes are continuously formed in a first metal laminate continuously supplied by a roll-to-roll device, and then each hole formed is plated, and a photoresist film or the like is laminated on a metal foil (e.g., copper foil) including a plating film, and then exposed, developed, and etched to form a first circuit pattern (112). As a result, a first circuit board (110) including a first thermoplastic resin layer (111) and first circuit patterns (112) respectively disposed on both sides of the first thermoplastic resin layer (111) can be obtained.

[0141] The device used in the above hole processing is not particularly limited as long as it is a device capable of opening a hole in a metal laminate, and includes, for example, a punching machine such as a metal punching machine or a rotary punching machine, a laser device, etc.

[0142] Alkaline developers that can be used in the above development process include, but are not limited to, aqueous solutions of quaternary ammonium hydroxides such as tetramethylammonium hydroxide and tetraethylammonium hydroxide; aqueous solutions of amines such as ammonia, ethylamine, diethylamine, and triethylamine.

[0143] The etchant that can be used in the above etching treatment process is not particularly limited as long as it is a generally used etchant in the art, and for example, an etchant such as hydrogen peroxide / hydrochloric acid (H2O2 / HCl); a copper etchant such as cupric chloride (CuCl2) or ferric chloride (FeCl3); or an etchant such as CNNBSA (3-nitrobenzene sulfonic acid) / PEI (polyethylenimine) can be used alone or in an appropriate mixture.

[0144] (S200) Step: Preparation of metal laminate

[0145] A metal laminate (120a) is prepared, which includes a metal foil (122a) and a dry film (121a) of a thermoplastic resin composition (C2) disposed on one surface of the metal foil (122a). This step (S200) has no temporal precedence with the step (S100).

[0146] The metal laminate (hereinafter, “second metal laminate”) (120a) obtained in the above step (S200) is of roll type and includes a metal foil (122a); and a dry film (hereinafter, “second dry film”) (121a) of a second thermoplastic resin composition (C2) disposed on one surface of the metal foil (122a).

[0147] This second metal laminate (120a) can be manufactured through various methods known in the art.

[0148] For example, a second thermoplastic resin composition (C2) may be directly applied onto one surface of a second metal foil (122a) and dried to obtain a second metal laminate (120a) including a second metal foil (122a) and a second dry film (121a). In this case, when a roll-to-roll device is used, the second dry film (121a) may be continuously formed on the second metal foil (122a) continuously supplied from a metal foil supply roller to obtain a roll-type second metal laminate (120a).

[0149] The above second metal foil (122a) may be different from or identical to the first A and first B metal foils. Since the description of the second metal foil (122a) is the same as that described in the first A and first B metal foil sections, it is omitted.

[0150] The above dry film (121a) is obtained by drying the second thermoplastic resin composition, and is later formed into a second thermoplastic resin layer (121) through a hot press process.

[0151] The second thermoplastic resin composition (C2) may include a second fluororesin filler, a second inorganic filler, and a second binder resin. Optionally, the second thermoplastic resin composition (C2) may additionally include a second organic solvent.

[0152] The above second fluororesin filler, like the first fluororesin filler, is a particle-type organic filler such as powder in a solid state at room temperature (about 20±5°C). This second fluororesin filler maintains its particle form when the second thermoplastic resin composition (C2) is dried, and is bound together with the second inorganic filler by the second binder resin, and is subsequently melted by high-temperature pressing and included in the second thermoplastic resin layer (121) as a polymer matrix component together with the second binder resin. Therefore, the second fluororesin filler can not only implement low dielectric constant and low dielectric loss characteristics of the second thermoplastic resin layer, but also improve heat resistance.

[0153] Examples of the second fluorine resin filler usable in the present invention are omitted because they are the same as those described in the first fluorine resin filler section.

[0154] The second fluororesin filler may have the same or different components as the first fluororesin filler. However, in the present invention, in order to directly attach the first circuit board (110) and the second metal laminate (120a) without a bonding sheet, the MFR of the second dry film (121a) is preferably greater than the MFR of the first thermoplastic resin layer (111), so that the MFR of the second fluororesin filler is greater than the MFR of the first fluororesin filler.

[0155] For example, the MFR of the second fluororesin filler may be in the range of 2 to 20 times that of the first fluororesin filler.

[0156] As another example, the MFR of the second fluororesin filler is in the range of 0.01 to 40 g / 10 min under a temperature of 372°C and a load of 5 kg, but is greater than the MFR of the first fluororesin filler. Here, the MFR (Melt Flow Rate) of the second fluororesin is measured as the total amount of extruded resin for 10 min under the conditions of 372°C and 5 kg according to the ISO 12086-2 test method. If the second fluororesin is a mixture of two or more types, the MFR of the mixture is measured.

[0157] The second fluororesin filler may include two or more types of fluororesin fillers having different MFRs. For example, the second fluororesin filler may include a second A fluororesin (e.g., PTFE, etc.) having an MFR of about 0.01 to 1 g / 10 min at a temperature of 372° C. and a load of 5 kg; and a second B fluororesin having an MFR of about 1 to 5 g / 10 min. In this case, the content of the second A fluororesin filler may be the same as the content of the second B fluororesin filler or less than twice the content of the second B fluororesin filler.

[0158] For example, the second fluororesin filler may include PFA and PTFE. At this time, the weight ratio of PFA and PTFE (PFA:PTFE) may be 20:80 to 80:20, but is not limited thereto.

[0159] As another example, the second fluororesin filler may include at least one selected from the group consisting of (a) PTFE and; (b) PFA and FEP. At this time, the usage ratio of PTFE and PFA and / or FEP (PTFE: PFA and / or FEP) may be 1:1 to less than 2:1 by weight. In addition, when PTFE is used together with PFA and FEP as the second fluororesin filler, the content of PFA may be adjusted to be equal to or less than the content of FEP so that the MFR of the second thermoplastic resin layer (121) is greater than the MFR of the first thermoplastic resin layer. Here, PFA and / or FEP means PFA, or FEP, or a mixture of PFA and FEP.

[0160] As another example, the first fluororesin filler comprises (a) PTFE; and (b) PFA, wherein the content of PTFE may be greater than the content of PFA. The usage ratio of PTFE and PFA (PTFE:PFA) may be 1:1 to less than 2:1 by weight.

[0161] In addition, the average particle diameter (D50) of the second fluororesin filler may be in the range of about 5 to 30 μm. If the second fluororesin filler has the above-mentioned average particle diameter, the second fluororesin filler can be uniformly dispersed without agglomeration in the second thermoplastic resin composition (C2), and the handling property of the second thermoplastic resin composition (C2) after coating can be improved. At this time, in the present invention, as the second fluororesin filler, one type of fluororesin filler having the same average particle diameter can be used alone, or two or more types of fluororesin fillers having different average particle diameters can be used in combination. Here, the average particle diameter (D50) of the second fluororesin filler can be measured according to the ASTM D4464-10 test method.

[0162] According to an example, the second fluororesin filler has an average particle diameter (D) of 20 to 30 μm. 50) having a second A fluorine resin filler; and an average particle diameter (D) of 5 to 10 μm 50 ) may include a second-B fluorine resin.

[0163] In addition, the second fluororesin filler can have a relative permittivity (Dk) of about 2.0 to 2.1 and a dielectric loss tangent (Df) of 0.0001 to 0.002 at 25°C and 10 GHz. In this way, since the second fluororesin filler has low dielectric properties, the low permittivity and low dielectric loss properties of the second thermoplastic resin layer (121) can be implemented. Here, the relative permittivity (Dk) and the dielectric loss tangent (Df) of the second fluororesin filler are measured under the conditions of 25°C and 10 GHz according to the split post dielectric resonator (SPDR) method (IEC 61189-2-721 test method).

[0164] In addition, the shape of the second fluororesin filler is not particularly limited, and includes, for example, spherical, flake, dendrite, conical, pyramidal, and amorphous shapes, and these may be used alone or in combination of two or more. In one example, the shape of the second fluororesin filler may be spherical. In this case, since the surface area of ​​the second fluororesin filler is minimized, the processing characteristics of the second thermoplastic resin composition can be improved, and isotropic characteristics can be imparted to the second thermoplastic resin layer.

[0165] In the second thermoplastic resin composition (C2) of the present invention, the content of the second fluororesin filler may be in the range of about 50 to 80 wt% based on the total weight of the resin composition. By adjusting the content of the second fluororesin filler within the above-described range, the resin composition can form a resin layer having a low dielectric constant.

[0166] For example, when the second fluororesin filler includes PTFE and PFA in a weight ratio of 2:1, and the content of the second fluororesin filler is adjusted to about 50 wt%, the content of the second inorganic filler is adjusted to about 45 wt%, and the content of the second binder resin is adjusted to about 5 wt%, the MFR of the second thermoplastic resin layer may be 5 g / 10 min.

[0167] As another example, when the second fluororesin filler includes PTFE and PFA in a weight ratio of 1:1, and the content of the second fluororesin filler is adjusted to about 80 wt%, the content of the second inorganic filler is adjusted to about 17 wt%, and the content of the second binder resin is adjusted to about 3 wt%, the MFR of the second thermoplastic resin layer may be less than about 1 g / 10 min.

[0168] In the second thermoplastic resin composition (C2) according to the present invention, the second inorganic filler can reduce the difference in coefficient of thermal expansion (CTE) between the second thermoplastic resin layer (121) and another layer [e.g., the second circuit pattern (122)], thereby improving the bending characteristics, low expansion, mechanical strength (toughness), and low stress of the second circuit board (120).

[0169] The above second inorganic filler may be identical to or different from the first inorganic filler in at least one of the components, size (e.g., maximum particle diameter, average particle diameter), and shape. The description of this second inorganic filler is omitted as it is the same as that described in the first inorganic filler section.

[0170] In the second thermoplastic resin composition (C2) of the present invention, the content of the second inorganic filler may be in the range of about 20 to 50 wt%, specifically about 30 to 45 wt%, based on the total amount of the resin composition. If the content of the second inorganic filler is less than about 20 wt%, the effect of reducing the dielectric constant may be insignificant, and on the other hand, if the content of the second inorganic filler exceeds about 50 wt%, the moldability of the resin composition may deteriorate.

[0171] According to an example, when the first fluororesin filler of the first thermoplastic resin composition and the second fluororesin filler of the second thermoplastic resin composition have the same components and contents, the content of the second inorganic filler in the second thermoplastic resin composition is adjusted to be smaller than the content of the first inorganic filler in the first thermoplastic resin composition (C1). In this case, the MFR of the second dry film (121a) can be adjusted to be larger than the MFR of the first thermoplastic resin layer (111). Therefore, the present invention can directly attach the first circuit board (110) and the second circuit board (120) without a bonding sheet.

[0172] The method for applying (coating) the above second thermoplastic resin composition is not particularly limited, and includes, for example, a roll-to-roll coating method, and specifically, comma coating, slot die coating, curtain coating, and spray coating.

[0173] The above drying process is to dry the second thermoplastic resin composition, and in particular, to remove the organic solvent within the composition. This drying process can be performed at a temperature of about 100°C or lower, specifically about 30 to 80°C, for about 1 to 5 minutes. As a result, a second metal laminate (120a) can be obtained in which a second dried film (121a) in which the second thermoplastic resin composition (C2) is dried is formed on a second metal foil (122a). In this way, the present invention only dries the second thermoplastic resin composition and does not perform a high-temperature firing process of 300°C or higher. Therefore, the second dried film (121a) obtained through the above drying process can be a sponge-shaped insulating layer having numerous pores therein.

[0174] However, in the present invention, the MFR of the second drying film (121a) is adjusted to be greater than the MFR of the first thermoplastic resin layer (111) of the first circuit board (110) described above. Accordingly, in the present invention, the second metal laminate (120a) can be laminated with the first circuit board (110) obtained in the above step (S10) without a bonding sheet in the following step (S40), and at this time, the dimensional stability of the first circuit board (110) can be prevented from being deteriorated.

[0175] (S300) Step: Formation step of the first multilayer laminate

[0176] On both sides of the carrier film (10), the first circuit board (110) obtained in step (S100) is laminated to form a first multilayer laminate. The first multilayer laminate formed in this step may have a structure in which the first circuit board (110) / carrier film (10) / first circuit board (110) are laminated in that order.

[0177] As shown in part I of FIG. 1, when a roll-to-roll device is used, the carrier film (10) is continuously supplied from a carrier film supply roller, and the first circuit board (110) is continuously supplied from each first circuit board supply roller, so that the first multilayer laminate can also be formed continuously.

[0178] The above laminating process can be performed using a pair of laminating rollers.

[0179] The above carrier film (10) is a kind of release film for interlayer separation (peeling), and while the first circuit board (110) can be stably adhered, the first circuit board can be easily detached (separated) by a predetermined external force.

[0180] The carrier film (10) usable in the present invention may be a polyimide (PI) film, but is not limited thereto.

[0181] A release layer may be disposed on the surface of the carrier film (10). The release layer can easily separate the first circuit pattern (111) or the first thermoplastic resin layer (112) of the first circuit board (110) from the carrier film (10) without damage and while maintaining its shape.

[0182] The release agent of the above release layer is not particularly limited, and examples thereof include epoxy-based release agents, fluororesin-based release agents, silicone-based release agents, alkyd resin-based release agents, and water-soluble polymers. In addition, if necessary, the release layer may include powder fillers, such as silicone and silica, as components. At this time, the fine particle powder filler may be a mixture of two types of powder fillers, and at this time, the average particle size thereof may be appropriately selected in consideration of the surface roughness to be formed.

[0183] The thickness of this heterogeneous layer can be appropriately adjusted within a conventional range known in the art.

[0184] In the present invention, the thickness of the carrier film (10) is not particularly limited and can be adjusted within a typical range known in the art, for example, it can be about 25 to 100 μm.

[0185] The release force of this carrier film (10) is not particularly limited and may be, for example, about 1 to 10 gf / inch.

[0186] The method for forming the heterogeneous layer is not particularly limited, and known methods such as heat pressing, heat roll lamination, extrusion lamination, application of a coating solution, and drying can be employed.

[0187] (S400) Step: Formation step of the second multilayer laminate

[0188] A second metal laminate (120a) obtained in step (S200) is laminated on both sides of the first multilayer laminate obtained in step (S300) to form a second multilayer laminate. At this time, the second dry film (121a) of the second metal laminate (120a) is in contact with the first circuit board (110).

[0189] As shown in part II of Fig. 1, when using a roll-to-roll device, a second metal laminate (120a) continuously supplied from a metal laminate supply roller is laminated on both sides of the first multilayer laminate continuously supplied in step (S300), thereby continuously forming a second multilayer laminate.

[0190] The above laminating process can be performed using a pair of laminating rollers.

[0191] The second B multilayer laminate obtained in the step (S400) may include a first B multilayer laminate including a carrier film (10) and first circuit boards (110) respectively disposed on both sides thereof; and second metal laminates (120a) respectively disposed on both sides of the first B multilayer laminate. Specifically, the second B multilayer laminate may have a structure in which the second metal foil (122a) / second dry film (121a) / first circuit pattern (112) / first thermoplastic resin layer (111) / first circuit pattern (112) / carrier film (10) / first circuit pattern (112) / first thermoplastic resin layer (111) / first circuit pattern (112) / second dry film (121a) / second metal foil (122a) are laminated in this order. At this time, the second drying film (121a) can come into contact with not only the first circuit pattern (112), but also the first thermoplastic resin layer (111).

[0192] Optionally, a protective metal foil (20) may be laminated on each side of the second multilayer laminate obtained in the above step (S400).

[0193] As shown in part Ⅲ of Fig. 1, when using a roll-to-roll device, a protective metal foil (20) continuously supplied from a protective metal foil supply roller is laminated on both sides of the second multilayer laminate obtained in step (S400) to continuously form a secondB multilayer laminate.

[0194] The protective metal foil (20) usable in the present invention is not particularly limited, and may be, for example, one type of metal foil selected from the group consisting of copper (Cu), iron (Fe), nickel (Ni), titanium (Ti), aluminum (Al), silver (Ag), and gold (Au), or two or more types of alloy foils. For example, the protective metal foil (20) may be a copper foil. In this case, any conventional copper foil known in the art can be used without limitation, and any copper foil manufactured by a rolling method or an electrolytic method can be used.

[0195] The laminating process of the above protective metal foil can be performed using a pair of laminating rollers.

[0196] (S500) Step: Hot press step of the 2B multilayer laminate

[0197] The second multilayer laminate obtained in the above step (S400) is hot pressed. At this time, the 2B multilayer laminate may be used instead of the second multilayer laminate.

[0198] Since both the second dry film (121a) and the first thermoplastic resin layer (111) in the second multilayer laminated plate contain thermoplastic components, they can be plastically deformed by heat. Therefore, when the second multilayer laminated plate is hot-pressed, the second dry film (121a) is melted by heat, has fluidity, and spreads. At this time, the first thermoplastic resin layer (111) can be melted or non-melted. If the first thermoplastic resin layer (111) is also melted by heat, since the MFR of the first thermoplastic resin layer (111) is smaller than the MFR of the second dry film (121a), unlike the second dry film (121a), only the resin layer at the interface with the second dry film (121a) has fluidity and spreads. The components of the second dry film (121a) that are spread and the components of the first thermoplastic resin layer (111) can be mixed with each other at the interface to fill the space between the first circuit patterns (112) without air bubbles. Thereafter, when the second multilayer laminate is cooled, the molten second dry film (121a) solidifies into the second thermoplastic resin layer (121), and the molten first thermoplastic resin layer (111) also solidifies again. At this time, the second thermoplastic resin layer (121) and the first thermoplastic resin layer (111) are attached and integrated as one film without a different interface. Therefore, the printed circuit board of the present invention can include a first circuit board (110) and a second circuit board (120) that are directly attached to each other without a bonding sheet.

[0199] This step (S500) can be performed using a roll-to-roll device, as illustrated in part Ⅳ of Fig. 1. In this case, the second multilayer laminated plate continuously supplied in the step (S400) can be continuously thermo-compression-bonded.

[0200] The above hot press process can utilize a pair of heating rollers, or a belt press comprising multiple pairs of heating rollers. In particular, when utilizing a belt press, since the pressure and temperature of each heating roller can be controlled, the temperature and pressure of the compression molding step and the firing step can be controlled differently.

[0201] The step (S500) above may include a step (S510) of compression-molding the second B multilayer laminate obtained in the step (S400); and a step (S520) of sintering the compression-molded multilayer laminate.

[0202] The above compression molding step (hereinafter, '(S510) step') is a low-temperature, high-pressure compression molding process. In the (S510) step, when pressure is applied to the second drying film (122a), the second fluorine resin fillers in the second drying film (122a) are compressed by the high pressure, and air bubbles between the fillers can be removed.

[0203] The above step (S510) can be performed for about 30 to 90 minutes under a pressure in the range of about 3 to 5 MPa. During this compression molding, the multilayer laminate can be preheated. The preheating temperature is not particularly limited, but is preferably lower than the melting point (Tm) of the second dry film, specifically lower than the melting point (Tm) of the second fluororesin filler. For example, the preheating temperature may be lower than 300°C, specifically about 200 to 280°C. In this case, this is based on the actual temperature applied to the actual product, and the actual press conditions may vary.

[0204] The above-mentioned firing step (hereinafter, '(S520) step') is preferably performed under a lower pressure than the above-mentioned compression molding step. Thus, the fluidity of the first thermoplastic resin layer (111) during firing can be minimized, thereby ensuring dimensional stability. In one example, the above-mentioned (S42) step can be performed under a pressure of less than 2 MPa, specifically, about 0.5 to 1 MPa.

[0205] This (S520) step may include (S521) a step of heat-treating the compression-molded multilayer laminate at a temperature higher than the melting point (Tm) of the second dry film and a pressure lower than the pressure during the compression molding; (S522) a step of stabilizing the heat-treated multilayer laminate while applying pressure up to the pressure during the compression molding at a temperature lower than the melting point (Tm) of the second dry film; and (S523) a step of cooling the stabilized multilayer laminate.

[0206] An example of the heat treatment temperature may be about 305°C or higher, specifically about 330 to 380°C, and more specifically about 330 to 350°C. In one example, the heat treatment step [hereinafter, '(S521) step'] may be performed at a temperature of about 305°C or higher, at a pressure lower than the pressure during the compression molding, for example, at a pressure of about 0.5 to 2 MPa, for about 30 to 90 minutes. In this case, the fluidity of the second fluororesin filler within the second dry film (121a) may be further improved, so that the diffusion effect may be further improved.

[0207] The above stabilization step [hereinafter, step (S522)] can be performed at a temperature of less than about 300°C, specifically about 200 to 280°C, and more specifically about 250 to 280°C. In one example, the stabilization step stabilizes the heat-treated multilayer laminate while applying pressure at a temperature of less than 300°C, for example, up to a pressure of about 3 to 5 MPa during compression molding. As a result, the thickness stability of each resin layer can be secured.

[0208] The above cooling step [hereinafter, step (S523)] can be performed under the same pressure as the stabilization step while cooling the stabilized multilayer laminate.

[0209] (S600) Step: Formation of the second circuit pattern

[0210] Although not shown, the second metal foil (122a) of the second multilayer laminate hot-pressed in the above step (S500) is processed into a second circuit pattern (122). Through this step (S600), the present invention can obtain a third multilayer laminate having a structure laminated in the order of second circuit board (120) / first circuit board (110) / carrier film (10) / first circuit board (110) / second circuit board (120).

[0211] In the above step (S600), a photoresist film or the like is laminated on the second metal foil (122a), then exposed, developed, and then etched to form a second circuit pattern (122).

[0212] Descriptions of the above exposure process, development process, and etching treatment process are omitted because they are the same as those described in the above step (S50).

[0213] The above exposure process forms a cured area and a non-cured area by exposure, and depending on whether the photoresist film is positive or negative, the non-exposed area or the exposed area is later removed by a developer.

[0214] This exposure process can be performed using an excimer laser, ultraviolet rays, ultraviolet rays, visible light, electron rays, X-rays, or g-rays (wavelength about 436 nm), i-rays (wavelength about 365 nm), h-rays (wavelength about 405 nm), or a mixture of these rays.

[0215] The above development process removes uncured areas by developing a partially exposed photoresist film with an alkaline developer. Examples of the alkaline developer include, but are not limited to, aqueous solutions of quaternary ammonium hydroxides such as tetramethyl ammonium hydroxide and tetraethyl ammonium hydroxide; aqueous solutions of amines such as ammonia, ethylamine, diethylamine, and triethylamine.

[0216] The above etching treatment process forms a second circuit pattern (122) by etching a portion of a second metal foil from which a certain area of ​​a photoresist film has been removed using an etchant. Non-limiting examples of the etchant include a hydrogen peroxide / hydrochloric acid (H2O2 / HCl) etchant; a copper etchant such as cupric chloride (CuCl2) or ferric chloride (FeCl3); or CNNBSA (3-nitrobenzene sulfonic acid) / PEI (polyethylenimine), and these may be used alone or in an appropriate combination of two or more.

[0217] Although not shown, in the present invention, before or after forming the second circuit pattern, a plurality of holes (H) can be processed in the hot-pressed second B multilayer laminate, and then the plurality of holes can be plated to form vias (Vis).

[0218] The device used in the above hole processing is not particularly limited as long as it is a device capable of opening a hole in a metal laminate, and includes, for example, a punching machine such as a metal punching machine or a rotary punching machine, a laser device, etc.

[0219] The method for forming the above plating film is not particularly limited and can be performed according to a conventional method known in the art.

[0220] (S700) Step: Separation step of multilayer printed circuit board

[0221] By separating the carrier film (10) and the first circuit board (110) from the third multilayer laminate obtained in the above (S600), two multilayer printed circuit boards in which the first circuit board (110) and the second circuit board (120) are laminated can be obtained simultaneously.

[0222] As shown in part V of Fig. 1, when the first circuit boards (110) on both sides of the third multilayer laminate continuously supplied in (S600) are separated (detached) from the carrier film (10), two multilayer printed circuit boards in which the first circuit board (110) and the second circuit board are laminated can be obtained at once. The multilayer printed circuit board can be wound on a winding roller and stored and moved.

[0223] According to an example, a multilayer printed circuit board (100A) manufactured by the present invention, as illustrated in FIG. 2, does not include a bonding sheet, and includes a first circuit board (110) including a first thermoplastic resin layer (111) and a first circuit pattern (112) disposed on at least one surface of the first thermoplastic resin layer (111); and a second circuit board (120) including a second thermoplastic resin layer (121) disposed on at least one surface of the first circuit board (110) and a second circuit pattern (122) disposed on one surface of the second thermoplastic resin layer (121), wherein a melt flow rate (MFR) of the second thermoplastic resin layer (111) is greater than an MFR of the first thermoplastic resin layer (121). Optionally, the first circuit board (110) may additionally include a fiber-containing substrate (113) embedded in the first thermoplastic resin layer (111) (see FIG. 3).

[0224] Although not shown, the multilayer printed circuit board (100A) of the present invention may additionally include a via that is formed by penetrating at least one of the first thermoplastic resin layer (111) and the second thermoplastic resin layer (121) and electrically connecting between the first circuit patterns (112) and / or between the first circuit pattern (112) and the second circuit pattern (122).

[0225] A protective metal foil (20) may be laminated on the second circuit board (120) of the multilayer printed circuit board to be separated. In this case, the protective metal foil (20) may additionally be separated from the multilayer printed circuit board. The separated protective metal foil (20) may be re-wound on a winding roller and reused. However, the protective metal foil (20) may also be separated from the third multilayer laminate before the separation of the multilayer printed circuit board.

[0226] Meanwhile, the carrier film (10) separated from the multilayer printed circuit board can be re-wound on a winding roller and reused.

[0227] (S800) Step: Repeatedly performing the step of forming the first multilayer laminate or the step of separating the multilayer printed circuit board

[0228] Optionally, the present invention further includes, after the hole plating step, a step of preparing an nth metal laminate comprising an nth metal foil and an nth dry film of a thermoplastic resin composition disposed on one surface of the nth metal foil; and, after the step of separating the multilayer printed circuit board, the step of forming the first multilayer laminate or the step of separating the multilayer printed circuit board may be repeated once or a plurality of times (wherein, n is an integer of 3 or more, specifically, an integer of 3 to 10). In this case, the first multilayer laminate may be formed using the multilayer printed circuit board separated in the step (S700) instead of the first circuit board (110), and the n-1th metal laminate may be used instead of the metal laminate (120a) to form a second multilayer laminate. However, in the present invention, in order to manufacture a multilayer printed circuit board with each circuit board attached without a bonding sheet, the MFR of each dry film is adjusted to increase gradually as it goes from the first thermoplastic resin layer (111) to the n-th dry film.

[0229] For example, the present invention can prepare a third metal laminate including a third metal foil and a third dry film of a third thermoplastic resin composition disposed on one surface of the third metal foil after the step (S700). At this time, the MFR of the third dry film is adjusted to be greater than the MFR of the second dry film. Thereafter, the multilayer printed circuit board obtained in the step (S700) is laminated on both surfaces of a carrier film (10) to form a first multilayer laminate, and then the third metal laminate prepared on both surfaces of the first multilayer laminate is laminated to form a second multilayer laminate. Next, after hot-pressing the second multilayer laminate, the third metal foil is processed into a third circuit pattern, and by processing holes and then plating holes, a third multilayer laminate having a structure of third circuit board (130) / second circuit board (120) / first circuit board (110) / carrier film (10) / first circuit board (110) / second circuit board (120) / third circuit board (130) can be obtained. Thereafter, by performing the step (S700), two multilayer circuit boards in which the first circuit board / second circuit board / third circuit board are sequentially laminated can be obtained simultaneously.

[0230] Optionally, after laminating a protective metal foil (20) on both sides of the second multilayer laminate, the protective metal foil may be hot pressed, and then the third metal foil may be processed into a third circuit pattern, and after hole processing, hole plating may be performed.

[0231] Also optionally, the step of preparing an n-th metal laminate, the step of forming a 2B multilayer laminate, the hot press step, the circuit pattern forming step, the hole processing step, and the hole plating step are repeatedly performed to manufacture a third multilayer laminate having a structure of an n-th circuit board / … / a third circuit board (130) / a second circuit board (120) / a first circuit board (110) / a carrier film (10) / a first circuit board (110) / a second circuit board (120) / a third circuit board (130) / … / a n-th circuit board, wherein n is an integer of 3 or more, and specifically, an integer of 3 to 10. The n-th metal laminate includes an n-th metal foil and an n-th dry film of a thermoplastic resin composition disposed on one surface of the n-th metal foil. At this time, the MFR of each dry film is controlled to gradually increase from the first thermoplastic resin layer to the n-th dry film. Afterwards, by performing the above step (S700), two multilayer circuit boards in which the first circuit board / second circuit board / third circuit board / … / nth circuit board are sequentially stacked can be obtained simultaneously.

[0232] However, in the present invention, in order to directly attach the n-th dry film to the n-1-th thermoplastic resin layer without a bonding sheet, the MFR of each dry film is adjusted to gradually increase from the first thermoplastic resin layer toward the n-th dry film (here, n is an integer greater than or equal to 3, specifically, an integer from 3 to 10). For example, the MFR of the second thermoplastic resin layer (121) is greater than the MFR of the first thermoplastic resin layer (111), and the MFR of the third dry film is greater than the MFR of the second thermoplastic resin layer (121).

[0233] For example, as one moves from the first thermoplastic resin layer (121) toward the n-th drying film, the MFR of the n-th drying film may increase by 2 to 10 times compared to the MFR of the n-1 thermoplastic resin layer. For example, as one moves from the first thermoplastic resin layer (111) toward the third drying film, the MFR of the second thermoplastic resin layer (121) may increase by 2 to 10 times the MFR of the first thermoplastic resin layer (111), and the MFR of the third drying film (131) may increase by 2 to 10 times the MFR of the second thermoplastic resin layer (121).

[0234] For example, the MFR of the first thermoplastic resin layer (111) may be in the range of 0.01 to 1 g / 10 min at a temperature of 372° C. and a load of 5 kg, the MFR of the second thermoplastic resin layer (121) may be in the range of more than 1 g / 10 min to 5 g / 10 min at a temperature of 372° C. and a load of 5 kg, and the MFR of the third dry film may be in the range of 5 to 50 g / 10 min, specifically 20 to 30 g / 10 min, at a temperature of 372° C. and a load of 5 kg.

[0235] According to another example, as one moves from the first thermoplastic resin layer (110) toward the n-th drying film, the melting point (Tm) of each drying film may gradually decrease. At this time, as one moves from the first thermoplastic resin layer (110) toward the n-th drying film, the content of the fluorine resin filler having a low melting point (Tm) in the resin composition forming each drying film may be adjusted to gradually increase.

[0236] For example, the first thermoplastic resin composition forming the first thermoplastic resin layer (111) may mainly include PTFE (Tm: about 317 to 337 °C) as the first fluororesin filler, the second thermoplastic resin composition forming the second thermoplastic resin layer (121) may mainly include PFA (Tm: about 302 to 310 °C) as the second fluororesin filler, and the third thermoplastic resin composition forming the third dry film (131) may mainly include FEP (Tm: 260 to 282 °C) as the third fluororesin filler. That is, the content ratio in each resin layer is adjusted to increase in the order of PTFE -> PFA -> FEP as it goes from the first thermoplastic resin layer (111) to the third dry film side.

[0237] For another example, the first thermoplastic resin composition forming the first thermoplastic resin layer (111) includes PTFE (Tm: about 317 to 337 °C) and PFA (Tm: about 302 to 310 °C) as first fluororesin fillers, and at this time, PTFE is included in a larger amount than PFA (e.g., PTFE: PFA = 2:1 to 10:1 weight ratio), the second thermoplastic resin composition forming the second thermoplastic resin layer (121) includes PFA (Tm: about 302 to 310 °C) and PTFE (Tm: about 317 to 337 °C) as second fluororesin fillers in a weight ratio of less than 1:1 to 1:2, and the third thermoplastic resin composition forming the third dry film includes FEP (Tm: 260 to 282 °C) and PFA (Tm: about 302~310 ℃), and at this time, FEP may be contained in a larger amount than PFA (e.g., FEP: PFA = 1:1~10:1 weight ratio).

[0238] According to another example, when the components and contents of the fluororesin filler in the first thermoplastic resin composition to the nth thermoplastic resin composition are the same, the content of the inorganic filler in each dry film can be adjusted to gradually decrease as it goes toward the nth dry film in the first thermoplastic resin layer (110).

[0239] The multilayer printed circuit board (100B) obtained through the above-described (800) step includes a first circuit board (110); second circuit boards (120) arranged on both sides of the first circuit board (110); and third circuit boards (130) to n-th circuit boards arranged sequentially on the second circuit board (120) (wherein, n is an integer greater than or equal to 3, and specifically, an integer from 3 to 10).

[0240] For example, a multilayer printed circuit board (100B) manufactured by the present invention may include, as illustrated in FIG. 4, a first circuit board (110); a second circuit board (120) disposed on each of both sides of the first circuit board (110); and a third circuit board (130) disposed on the second circuit board (120).

[0241] At this time, the third circuit board includes a third thermoplastic resin layer disposed on the second circuit board, and a third circuit pattern disposed on one surface of the third thermoplastic resin layer, and the n-th circuit board includes an n-th thermoplastic resin layer disposed on the n-1-th circuit board, and an n-th circuit pattern disposed on one surface of the n-th thermoplastic resin layer, and the MFR of each thermoplastic resin layer gradually increases as it goes from the first thermoplastic resin layer to the n-th thermoplastic resin layer. However, the second circuit board (120), the third circuit board (130) to the n-th circuit board sequentially disposed on one surface of both surfaces of the first circuit board (110) may be omitted.

[0242] In addition, the multilayer printed circuit board (100B) of the present invention may further include a via that is formed by penetrating at least one of the first thermoplastic resin layer (111), the second thermoplastic resin layer (121), the third thermoplastic resin layer, …, the n-th thermoplastic resin layer, and electrically connects between the first circuit patterns (112), between at least one of the first circuit pattern (112), the second circuit pattern (122), the third circuit pattern (132), …, the n-th circuit pattern (here, n is an integer of 3 or more, specifically, an integer of 3 to 10).

[0243] As described above, the present invention not only enables the automatic and continuous manufacture of a multilayer printed circuit board that does not include a bonding sheet through roll-to-roll manufacturing of the entire process, but also improves the shortening of the manufacturing process time, mass production, and cost reduction effects.

[0244] The multilayer printed circuit board manufactured in the present invention can achieve environmental reliability and low dielectric loss in a high-frequency range because the circuit boards are built up by directly bonding them using a single material without a bonding sheet.

[0245] In addition, the multilayer printed circuit board manufactured by the present invention can implement a 3D-shaped circuit through bending and folding by making the product slimmer, and thus, processability can be improved.

[0246] In addition, the multilayer printed circuit board manufactured by the present invention has excellent low-loss characteristics in the high-frequency range because each thermoplastic resin layer contains a fluorine-based component.

Claims

1. A step of preparing a first circuit board including a first thermoplastic resin layer and a first circuit pattern arranged on at least one surface of the first thermoplastic resin layer; A step of preparing a metal laminate comprising a metal foil and a dry film of a thermoplastic resin composition disposed on one surface of the metal foil; A step of forming a first multilayer laminate by laminating the first circuit boards on both sides of a carrier film; A step of forming a second multilayer laminate by laminating the metal laminate on each side of the first multilayer laminate; A step of hot pressing the second multilayer laminate; A step of forming a second circuit pattern on the metal foil of the hot-pressed second multilayer laminate to form a third multilayer laminate; and A step of separating the carrier film and the first circuit board from the third multilayer laminated board to obtain two multilayer printed circuit boards in which the first circuit board and the second circuit board are laminated, respectively; Including, A method for manufacturing a multilayer printed circuit board, wherein the MFR of the above-mentioned drying film is adjusted to be greater than the MFR of the above-mentioned first thermoplastic resin layer.

2. In paragraph 1, A method for manufacturing a multilayer printed circuit board, wherein the MFR of the above-mentioned dry film is 10 to 100 times higher than the MFR of the above-mentioned first thermoplastic resin layer.

3. In paragraph 1, A method for manufacturing a multilayer printed circuit board, wherein the MFR of the first thermoplastic resin layer is in the range of 0.01 to 1 g / 10 min at a temperature of 372° C. and a load of 5 kg.

4. In paragraph 1, A method for manufacturing a multilayer printed circuit board, wherein the MFR of the above-mentioned dry film is more than 1 g / 10 min and less than or equal to 5 g / 10 min at a temperature of 372 ℃ and a load of 5 kg.

5. In paragraph 1, The first thermoplastic resin layer is formed of a first thermoplastic resin composition including a first fluorine resin filler, a first inorganic filler, and a first binder resin, The thermoplastic resin composition comprises a second fluorine resin filler, a second inorganic filler, and a second binder resin. A method for manufacturing a multilayer printed circuit board, wherein the MFR of the second fluorine resin filler is greater than the MFR of the first fluorine resin filler.

6. In paragraph 5, A method for manufacturing a multilayer printed circuit board, wherein the MFR of the second fluorine resin filler is 2 to 20 times greater than the MFR of the first fluorine resin filler.

7. In paragraph 5, A method for manufacturing a multilayer printed circuit board, wherein the content of the second inorganic filler in the second thermoplastic resin composition is less than the content of the first inorganic filler in the first thermoplastic resin composition.

8. In paragraph 1, A method for manufacturing a multilayer printed circuit board, wherein the above-mentioned drying film is directly attached onto the first circuit board.

9. In paragraph 1, A method for manufacturing a multilayer printed circuit board, wherein a fiber-containing substrate is embedded within the first thermoplastic resin layer.

10. In paragraph 1, The above hot press step A step of compression molding the second multilayer laminated plate; and A step of sintering the above compression-molded second multilayer laminated plate. Including, A method for manufacturing a multilayer printed circuit board, wherein the above-mentioned firing step is performed under a lower pressure than the above-mentioned compression molding step.

11. In paragraph 10, A method for manufacturing a multilayer printed circuit board, wherein the compression molding step is performed under a pressure in the range of 3 to 6 MPa.

12. In paragraph 10, The above firing step A step of heat-treating the compression-molded second multilayer laminate at a temperature higher than the melting point (Tm) of the dry film and under a pressure lower than the pressure at the time of compression molding; A step of stabilizing the heat-treated second multilayer laminate while applying pressure to the compression molding pressure at a temperature lower than the melting point (Tm) of the dry film; and A step of cooling the above stabilized second multilayer laminated plate. A method for manufacturing a multilayer printed circuit board, comprising:

13. In paragraph 1, Before or after the formation of the second circuit pattern, A step of processing a plurality of holes in the second multilayer laminate; and A step of forming a via by plating the above plurality of holes A method for manufacturing a multilayer printed circuit board, the method further comprising:

14. In paragraph 13, A step of preparing an nth metal laminate comprising an nth metal foil and an nth dry film of a thermoplastic resin composition disposed on one surface of the nth metal foil; further comprising; After the separation step of the above multilayer printed circuit board, The step of forming the first multilayer laminated plate or the step of separating the multilayer printed circuit board are performed once or multiple times. A first multilayer laminate is formed by using the separated multilayer printed circuit board instead of the first circuit board, A second multilayer laminate is formed by using the nth metal laminate instead of the above metal laminate, In the above first thermoplastic resin layer, as you go towards the nth drying film, the MFR of each drying film is adjusted to become larger. A method for manufacturing a multilayer printed circuit board, wherein n is an integer greater than or equal to 3.

15. In paragraph 14, A method for manufacturing a multilayer printed circuit board, wherein, as one moves toward the nth drying film side in the first thermoplastic resin layer, the MFR of each drying film gradually increases by 2 to 10 times.

16. In paragraph 14, A method for manufacturing a multilayer printed circuit board, wherein the melting point (Tm) of each drying film gradually decreases as it moves toward the nth drying film side in the first thermoplastic resin layer.

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