KR20210026756A - Flexible metal clad laminate and flexible metal composite substrate comprising the same - Google Patents

Abstract

The present invention provides a new flexible metal laminate which stabilizes heat generation characteristics, simplifies a manufacturing process, and reduces costs by having a binary or more multi-component alloy layer having a high resistivity value and a low resistance change rate according to a temperature change, and a flexible metal composite substrate having the laminate which can be applied to an optical module for optical communication.

Description

A flexible metal laminate and a flexible metal composite substrate including the same {FLEXIBLE METAL CLAD LAMINATE AND FLEXIBLE METAL COMPOSITE SUBSTRATE COMPRISING THE SAME}

The present invention is a ductile metal laminate comprising a binary or more multi-element alloy layer having a high specific resistance and a low resistance change rate depending on temperature, and a ductility that can be applied to an optical module for optical communication through stabilization of heat generation characteristics and cost reduction effect including the same. It relates to a metal composite substrate.

With the advent of the recent information age, optical communication technology capable of transmitting a large amount of information is becoming common, and the development of related technologies for optical modules is also accelerating. In general, a laser diode (LD), which is a light source of an optical module used for optical communication, has a lot of restrictions on the wavelength range due to a problem in which the wavelength changes as the temperature of the surrounding environment changes. In particular, in the case of a low-density wavelength multiplex (CWDM: Coarse Wavelength Division Multiplex) optical module, it is not a big problem in the general operating temperature range of 0 to 70 ℃, but in the case of industrial use, the operating temperature range is extended to -40 to 85 ℃. Accordingly, the temperature fluctuation range around the optical module is extended to a maximum of 125 ℃. As the wavelength of the laser diode LD changes to about 0.1 nm/°C according to such temperature change, interference between wavelength channels may occur.

On the other hand, since there is a limit to improving the characteristics of the laser diode (LD) itself, it is necessary to correct the temperature so that the laser diode disposed inside the optical module is not directly exposed to the external temperature environment, thereby satisfying the conditions of the wavelength range of the laser diode. Several technologies have been proposed.

As an example, there is a method of attaching a thin film heater to a system of an optical module. In this method, in order to satisfy the wavelength specifications of the laser diode used, the heater is operated below a specific temperature to increase the operating temperature of the entire optical module, thereby limiting the optical module from operating under a specific temperature. In this way, when heating the entire system of an optical module or the entire metal body constituting an optical subassembly (OSA) is required, the size of the parts to be heated is large and the number of parts is large, so the thermal efficiency is low. there is a problem. In addition, if a general heater is used, a separate control circuit for sensing the temperature and controlling the temperature is required to control the heater, so the circuit pattern of the printed circuit board (PCB) becomes complicated and a number of printed circuit boards are provided. Should be. As a result, there is a problem that not only an increase in assembly cost and an increase in assembly difficulty of the product is caused, but also contact failure occurs due to assembly of a number of parts, the manufacturing process is complicated, and occupies a lot of space, resulting in an increase in size.

The present invention was conceived to solve the above-described problems, and by providing a binary or higher multi-element alloy layer having a high specific resistance value and a low resistance change rate according to temperature change, it is possible to stabilize the heating characteristics, simplify the manufacturing process, and reduce the cost. It is an object of the present invention to provide a novel flexible metal laminate, including the same, and a flexible metal composite substrate that can be applied to an optical module for optical communication.

In order to achieve the above technical problem, the present invention is an insulating film; And at least a binary or higher alloy layer disposed on one or both surfaces of the insulating film and containing copper and nickel, wherein the specific resistance value of the alloy layer is 2.0 × 10 ^-8 Ω·m or more, and 50 to 100 It provides a flexible metal laminate having a resistance change rate of 0.05%/°C or less for each temperature at °C.

In one embodiment of the present invention, the alloy layer is a binary alloy containing copper and nickel; A ternary alloy containing copper, nickel, and a first metal (M _{1 );} Alternatively, a quaternary alloy containing copper, nickel, a first metal (M ₁ ) and a second metal (M ₂ ) may be included.

For example, in the binary alloy, the alloy ratio of copper and nickel may be from 54 to 58: 46 to 42 by weight.

In one embodiment of the present invention, the first metal (M ₁ ) included in the ternary alloy may be any one of Mn, Fe, Al, and C.

For example, in the ternary alloy, the alloy ratio of copper, nickel, and the first metal (M ₁ ) may be 53.9 to 56.5: 46 to 42: 0.1 to 1.5 weight ratio.

In one embodiment of the present invention, the second metal (M ₂ ) included in the quaternary alloy is any one of Mn, Fe, Al, and C, and may be different from _{the first metal (M 1 ).}

For example, in the quaternary alloy, the alloy ratio of copper, nickel, the first metal (M ₁ ) and the second metal (M ₂ ) is 53.8 to 56.5: 46 to 41: 0.1 to 1.5: 0.1 It may be ~ 1.0 weight ratio.

In one embodiment of the present invention, the thickness of the alloy layer may be 12 to 35 ㎛.

In one embodiment of the present invention, the surface roughness (Rz) of the alloy layer may be 1.0 μm or less.

For example, the insulating film may be a polyimide film or a polyimide film coated with a thermoplastic polyimide layer.

In one embodiment of the present invention, the polyimide film or the thermoplastic polyimide layer may further include at least one of a colorant and an inorganic filler, respectively.

For one embodiment of the present invention, the polyimide may be a transparent polyimide, a colored polyimide, or a black polyimide.

For example, an adhesive layer disposed between the insulating film and the alloy layer may be further included.

For example, in accordance with IPC-TM-650 2.4.9, the adhesive strength of the insulating film to the alloy layer (Peel stregth) may be 0.5 kgf/cm or more.

In addition, the present invention, a first coverlay film comprising a first polymer film and a first adhesive layer; A second coverlay film including a second polymer film and a second adhesive layer; It provides a flexible metal composite substrate comprising; and the above-described flexible metal laminate disposed between the first coverlay film and the second coverlay film.

In one embodiment of the present invention, the flexible metal laminate includes: (i) an insulating film; And a single-sided flexible metal laminate on which the first alloy layer is laminated. Or (ii) a first alloy layer; Insulating film; And a double-sided flexible metal laminate on which the second alloy layer is laminated.

In one embodiment of the present invention, the flexible metal composite substrate includes: a first coverlay film; Double-sided flexible metal laminate; And a second coverlay film is stacked, wherein the first alloy layer is disposed between the first adhesive layer of the first coverlay film and the insulating film, and the second alloy layer is a second coverlay film of the second coverlay film. 2 It is disposed between the adhesive layer and the insulating film, and they may be integrated.

In one embodiment of the present invention, the flexible metal composite substrate includes: a first coverlay film; Single-sided flexible metal laminate; Double-sided flexible metal laminate; And an adhesive layer disposed between the insulating film of the single-sided flexible metal laminate and the first alloy layer of the double-sided flexible metal laminate, wherein the second coverlay film is laminated, and these may be integrated.

In one embodiment of the present invention, at least one of the alloy layers may include one or more circuit patterns patterned in a predetermined shape.

In one embodiment of the present invention, the average operating temperature of the flexible metal composite substrate may be 65°C±10%, and the maximum temperature may be 120°C or less.

In one embodiment of the present invention, the flexible metal composite substrate may be applied to an optical module for optical communication.

In the present invention, by constructing a ductile metal laminate having a binary or higher multi-element alloy layer having a high specific resistance value and a low resistance change rate according to temperature, it can be applied to a heating element using resistance characteristics according to temperature.

In addition, since the flexible metal laminate can be applied without limitation, such as a conventional lamination method or casting method using a thin-film metal substrate, the processability is further improved, the manufacturing process is simplified, and the process cost is reduced. can do.

In addition, by modifying and controlling the components of the polyimide layer used as the insulating film, a flexible metal laminate having excellent high heat resistance and chemical resistance can be manufactured.

Accordingly, the above-described flexible metal laminate is applied to fields requiring stability of heat generation characteristics, for example, optical modules for optical communication, thereby reducing cost and weight, as well as improving workability in the assembly process, and electrical signals due to amplification of radio waves of optical communication. The loss rate of can be minimized.

The effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the present specification.

1 is a schematic cross-sectional view of a flexible metal laminate according to an embodiment of the present invention.
2 is a schematic cross-sectional view of a flexible metal laminate according to another embodiment of the present invention.
3 is a schematic cross-sectional view of a flexible metal laminate according to another embodiment of the present invention.
4 is a schematic cross-sectional view of a flexible metal composite substrate according to an embodiment of the present invention.
5 is a schematic cross-sectional view of a flexible metal composite substrate according to another embodiment of the present invention.
6 is a manufacturing process diagram of a flexible metal laminate according to an embodiment of the present invention.
7 is a manufacturing process diagram of a flexible metal laminate according to another embodiment of the present invention.
8 is a manufacturing process diagram of a flexible metal laminate according to another embodiment of the present invention.
9 is a manufacturing process diagram of a flexible metal laminate according to another embodiment of the present invention.
10 is a manufacturing process diagram of a flexible metal laminate according to another embodiment of the present invention.
11 is a surface SEM photograph (×6,000) of the binary copper-nickel alloy layer according to the present invention.
12 is a SEM photograph (×6,000) of the surface of a conventional copper layer.
13 is a graph showing a change in resistance according to temperature using a binary copper-nickel alloy layer (A) and a copper layer (B).

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments of the present invention are provided to more completely describe the present invention to those of ordinary skill in the art, and the following examples may be modified in various other forms, and the scope of the present invention is described below. It is not limited to examples. In this case, the same reference numerals refer to the same structure throughout the present specification.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used with meanings that can be commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not interpreted ideally or excessively unless explicitly defined specifically.

In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of description, so the present invention is not necessarily limited to the illustrated bar. In the drawings, the thicknesses are enlarged in order to clearly express various layers and regions. In addition, in the drawings, for convenience of description, the thicknesses of some layers and regions are exaggerated.

In addition, throughout the specification, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless otherwise stated. In addition, throughout the specification, the term "above" or "on" means not only the case that is located above or below the target part, but also includes the case where there is another part in the middle, and must always refer to the direction of gravity. It does not mean that it is located above the standard. In addition, in the present specification, terms such as "first" and "second" do not represent any order or importance, but are used to distinguish components from each other.

In addition, throughout the specification, the term "on a plane" means when the target part is viewed from above, and when "cross-sectional" refers to when the target part is viewed from the side when a vertically cut section is viewed from the side.

<Flexible metal laminate>

According to an embodiment of the present invention, there is provided a flexible metal laminate having a binary or more alloy layer containing copper (Cu) and nickel (Ni) as main components. Here, the flexible metal laminate is a material of a flexible printed circuit board (FPCB), and refers to a laminate in which an insulating film and an alloy layer are combined.

1 to 3 are cross-sectional views schematically showing the structure of a flexible metal laminate according to an embodiment of the present invention, for example, FIG. 1 is a cross-sectional flexible metal laminate including one alloy layer 10 ( 100) is a cross-sectional view, and FIGS. 2 to 3 are cross-sectional views of a double-sided flexible metal laminate 110 including two alloy layers 10.

Referring to FIG. 1, the flexible metal laminate 100 includes an insulating film 20; And a binary or higher alloy layer 10 disposed on one surface of the insulating film 20. Hereinafter, each configuration of the flexible metal laminate 100 will be described in detail.

Alloy layer

In the ductile metal laminate 100 of the present invention, the alloy layer 10 uses an alloy layer 10 having a higher specific resistance than a conventional copper foil and a lower resistance change rate for each temperature in a predetermined temperature range. Accordingly, it can be applied to a field that requires stable heat generation at a predetermined temperature.

The specific resistance (Ω·cm) of the alloy layer 10 may be at least 10 times higher than that of a conventional copper foil, specifically 20 times or more, and more specifically about 29 times. In addition, the resistance value of the alloy layer 10 may be at least 10 times higher than that of copper foil over room temperature and high temperature regions (eg, 30 to 200°C). For example, the specific resistance value of the alloy layer 10 may be 2.0 × 10 ^-8 Ω·m or more, and more specifically 40×10 ^-8 to 55×10 ^-8 Ω·m. Here, the resistance value is IPC-TM-650 2.5.17. It may be measured according to the test standard.

The alloy layer 10 is a constantan-based material, and may be a resistance alloy having an appropriate resistivity and a generally flat resistance/temperature curve. Constantan materials can suitably provide a temperature coefficient of less than 25 ppm/°C, preferably of less than about 10 ppm/°C. In addition, constantan materials provide good corrosion resistance. For example, the alloy layer 10 may have a temperature-specific resistance change rate of 0.05%/℃ or less at 50 to 100°C, specifically 0.001 to 0.03%/℃, and more specifically 0.001 to 0.003%/℃ Can be

The alloy layer 10 may be a binary or higher polyvalent alloy containing copper (Cu) and nickel (Ni) as main components while having the above-described specific resistance value, without limitation. Specifically, a binary alloy containing copper and nickel; A ternary alloy containing copper, nickel, and a first metal (M _{1 );} Alternatively, a quaternary alloy containing copper, nickel, a first metal (M ₁ ) and a second metal (M ₂ ) may be included.

For an embodiment of the present invention, in a binary alloy containing copper and nickel (Cu-Ni alloy), the alloy ratio of copper (Cu) and nickel (Ni) is 54 to 58: 46 to 42 weight ratio (%) It can be composed of.

, For another embodiment of the present invention, copper, nickel, and the first metal ternary alloy _{(Cu-Ni-M 1 alloy} ) In, Cu, Ni and the first metal (M ₁₎ containing an (M ₁₎ The alloy ratio may be composed of 53.9-56.5: 46-42: 0.1-1.5 weight ratio. At this time, the first metal (M ₁ ) included in the ternary alloy may be used without limitation, without limitation, a common component that may be added to the alloy in the art, and for example, it may be any one of Mn, Fe, Al, and C. have.

In another embodiment of the present invention, in a quaternary alloy (Cu-Ni-M ₁ -M ₂ alloy) _{containing copper, nickel, a first metal (M 1} ) and a second metal (M _{2 ),} The alloy ratio of copper, nickel, the first metal (M ₁ ) and the second metal (M ₂ ) may be 53.8 to 56.5: 46 to 41: 0.1 to 1.5: 0.1 to 1.0 weight ratio. The second metal (M ₂ ) included in the quaternary alloy may be used without limitation any component that can be added to the alloy in the art. For example, as any one of Mn, Fe, Al, and C, the first metal It may be different from (M _{1 ).} In the case of having the above alloy composition, since the specific resistance is approximately 20 times higher than that of the conventional copper foil, and the resistance change rate for each temperature is low in a predetermined temperature range (eg, 50-100°C), the heat generation characteristics can be continuously and stably maintained. It can be applied as a flexible metal composite substrate for heat generation provided in an optical module for optical communication.

The alloy layer 10 may be a conductor layer forming at least one circuit pattern. Such an alloy layer may form a circuit pattern portion or an antenna pattern portion, respectively, through conventional dry or wet etching known in the art. In this case, the circuit pattern portion or the antenna pattern portion may be formed to have the same or different predetermined area, line width, and shape, depending on the intended application.

The thickness of the alloy layer 10 is not particularly limited, and may be 12 to 35 µm, preferably 12 to 18 µm in consideration of the thickness, electrical and mechanical properties of the final product. In addition, the alloy layer 10 may be a rolled metal foil having an average roughness (Rz) of 1.0 or less, specifically 0.5 µm or less.

Insulating film

In the flexible metal laminate 100 of the present invention, the insulating film 20 is disposed on the adjacent alloy layer 10 to exhibit excellent adhesion and at the same time serve to make the alloy layer 20 electrically insulated from the outside. Do it.

The insulating film 20 may be used without limitation, a conventional polymer used in the art, for example, polyimide, polyamide, polyamideimide, polyamic acid resin, polyester, polyphenylene sulfide, polyester sulfone , Polyetherether ketone, aromatic polyamide, polycarbonate, and may include one or more selected from the group consisting of polyarylate. Preferably, it may be a polyimide (PI) film.

In the present invention, by applying a polyimide (PI) film as the insulating film 20, it is possible to exhibit flexibility and excellent thermal resistance characteristics, and at the same time exhibit the inherent physical properties of the polyimide.

Specifically, polyimide (PI) resin is a polymer material having an imide ring and exhibits excellent heat resistance, ductility, chemical resistance, abrasion resistance and weather resistance based on the chemical stability of the imide ring. It exhibits thermal expansion coefficient, low air permeability, and low dielectric properties. Therefore, when the polyimide resin is integrated with the alloy layer 10 and the copper layer 30, the flame retardancy of the flexible metal laminate 100 can be sufficiently secured due to the flame retardancy of the polyimide itself. In addition, the surface hardness increases, so that scratch resistance increases, and heat resistance increases due to a high glass transition temperature (Tg), and high flexibility compared to epoxy resins can be secured. In addition, it is possible to provide flexibility and excellent thermal resistance characteristics of the flexible metal laminate 100, and increase the degree of freedom in product design.

The insulating film 20 according to the present invention may be in the form of a self-supporting film or sheet, or may include a coating layer formed on the film or sheet.

For example, the insulating film 20 may be a polyimide (PI) film or a polyimide film coated with a thermoplastic polyimide layer (TPI).

The polyimide film may be manufactured according to a conventional method known in the art. Specifically, (i) a method of synthesizing a polyamic acid solution, which is a polyimide precursor, and then coating it on a substrate (eg, a polyimide film), and curing, (ii) a polyamic acid solution as a polyimide precursor. After synthesis, a chemical imidation method in which a catalyst and a dehydrating agent are reacted, (iii) a method of obtaining a salt or imide oligomer such as a half ester salt of tetracarboxylic dianhydride, and solid-phase polymerization thereof, or (iv ) There is a method of reacting tetracarboxylic dianhydride and diisocyanate. In addition, it may be prepared by using a commercially available thermosetting polyimide resin film, or coating a soluble polyimide (soluble PI) or polyamic acid solution on a substrate (eg, a polyimide film).

In the present invention, the polyimide resin or polyamic acid solution (polyimide precursor solution) may be formed by reacting an aromatic dianhydride and an aromatic diamine in the presence of a solvent. As the aromatic dianhydride material, conventional aromatic acid dianhydrides known in the art may be used without limitation. Non-limiting examples of aromatic dianhydrides that can be used include pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA: 3, 3',4,4'-biphenyltetracarboxylicdianhydride), 3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA: 3,3',4,4'-benzophenonetetracarboxylic dianhydride), 4,4'- Oxydiphthalic anhydride (ODPA: 4,4'-oxydiphthalic anhydride), 4,4'-(4,4'-isopropylidenediphenoxy)-bis-(phthalic anhydride) (BPADA: 4 ,4'-isopropylidenediphenoxy)-bis(phthalic anhydride), 2,2'-bis-(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA: 2,2'-bis-(3,4 -dicarboxyphenyl)hexafluoropropane dianhydride), ethylene glycol bis (anhydro-trimellitate) (TMEG: ethylene glycol bis (anhydro-trimellitate)), hydroquinone diphthalic anhydride (HQDEA: Hydroquinone diphthalic anhydride) and 3,4, 3',4'-diphenylsulfone tetracarboxylic dianhydride (DSDA: 3,4,3',4'-diphenylsulfonetetracarboxylicdianhydride), or a mixture of two or more thereof.

In addition, as the aromatic diamine material contained in the polyamic acid solution, conventional aromatic diamines known in the art may be used without limitation. Non-limiting examples of aromatic diamines that can be used include p-phenylenediamine (p-PDA), m-phenylenediamine (m-PDA:m-phenylene diamine), 4,4'-oxydianiline ( 4,4'-ODA:3,4'-oxydianiline), 2,2-bis(4-4[aminophenoxy]-phenyl)propane (BAPP:2,2-bis(4-[4-aminophenoxy]- henyl)propane), 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB-HG:2,2'-Dimethyl-4,4'-diaminobiphenyl), 1,3-bis (4 -Aminophenoxy) benzene (TPER: 1,3-bis (4-aminophenoxy) benzene), 2,2-bis (4-[3-aminophenoxy] phenyl) sulfone (m-BAPS: 2,2-bis (4-[3-aminophenoxy]phenyl) sulfone), 4,4'-diamino benzanilide (DABA:4,4'-diamino benzanilide), 4,4'-bis (4-aminophenoxy) biphenyl (4,4'-bis(4-aminophenoxy)biphenyl), or a mixture of two or more.

On the other hand, in the present invention, a polyimide resin for producing the polyimide film; And/or as at least one of an aromatic dianhydride and an aromatic diamine used in the synthesis of the polyimide precursor solution, one substituted with a fluorine atom may be used. Through this, even if a fluorine-based resin is not additionally included as in the prior art, characteristics of a low dielectric constant and a low dielectric loss rate can be secured due to the characteristics of a fluorine atom having a low polarity, and excellent chemical resistance can be secured by increasing rigidity. have.

The type of solvent used in the preparation of the polyamic acid solution is not particularly limited, and any organic solvent commonly used in the art may be used without limitation. Non-limiting examples of solvents that can be used include N-methylpyrrolidinone (NMP), N,N-dimethylacetamide (DMAc: N,N-dimethylacetamide), tetrahydrofuran (THF), N,N-dimethylformamide (DMF: N,N-dimethylformamide), dimethyl sulfoxide (DMSO: dimethylsulfoxide), cyclohexane (cyclohexane) and acetonitrile (acetonitrile) one or more materials selected from the group consisting of. .

In addition, the polyamic acid solution (polyimide precursor solution) used to form the polyimide film is dimensional stability, reducing the difference in coefficient of thermal expansion (CTE) between the polyimide film and the alloy layer 10 and the copper layer 30 In order to effectively improve the bending properties, low expansion, mechanical properties, and low stress of the final product, a conventional inorganic filler known in the art may be further included.

Non-limiting examples of inorganic fillers that can be used include silica, calcium carbonate, magnesium carbonate, alumina, magnesia, clay, talc, calcium silicate, titanium oxide, antimony oxide, glass fiber, aluminum borate, barium titanate, strontium titanate, calcium titanate. , Magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, calcium zirconate, boron nitride, silicon nitride, talc, and mica. The amount of the inorganic filler used is not particularly limited, and may be appropriately adjusted in consideration of the above-described bending characteristics and mechanical properties. The average particle diameter of the inorganic filler can be appropriately adjusted within a conventional range known in the art, and is not particularly limited. For example, it may be in the range of 0.1 to 10 μm.

When applied to a printed circuit board (PCB), the insulating film 20 may contain a laser energy absorbing component in order to further improve the workability of a hole by a laser. As the laser energy absorbing component, known ones such as carbon powder, metal compound powder, metal powder, or black dye can be used.

The polyimide film that can be used as the insulating film 20 of the present invention may be mounted inside a side mirror of an automobile. Accordingly, it may be a conventional transparent polyimide layer or a colored polyimide layer in the art. At this time, the colored polyimide layer includes a colored polyimide layer or a black polyimide layer.

According to an example of the present invention, the polyimide film may be a colored polyimide layer. At this time, the polyamic acid solution forming the polyimide film may further include a colorant. The material usable as a colorant is not particularly limited, and examples include at least one material selected from the group consisting of carbon black, cobalt oxide, Fe-Mn-Bi black, iron oxide black, and mica iron oxide known in the art. . Depending on the type of the colorant, the polyimide film may have colors such as black, dark gray, dark brown, dark brown, and white. In addition, the colorant may be present in an amount of 2 to 20% by weight based on the total weight of the colored polyimide layer.

In addition, the polyimide film may be a black polyimide layer. The polyamic acid solution constituting such a polyimide film may contain both a colorant and an inorganic filler, and specifically, may contain carbon black and silica particles. For a more specific example, the polyimide film preferably contains 3 to 10% by weight of carbon black and 1 to 10% by weight of silica particles.

Meanwhile, according to an example of the present invention, in order to provide heat resistance and durability by being provided in the flexible metal laminate 100, the glass transition temperature (Tg) of the polyimide film forming the insulating film 20 may be 200 to 400°C, and , Preferably it may be 320 to 370 ℃. By satisfying the above-described physical properties, it is possible to improve the physical stability of the product.

The thickness of the insulating film 20 can be appropriately adjusted in consideration of the handleability of the film, physical rigidity, coefficient of thermal expansion, thinning of the substrate, insulation, high-density wiring, and the like. For example, it may be 5 to 125 µm, preferably 12.5 to 50 µm, more preferably 12.5 to 25 µm. If necessary, the surface of the insulating film 20 may have been subjected to surface treatment such as mat treatment or corona treatment.

2 schematically shows a cross-sectional structure of a flexible metal laminate 110 according to another embodiment of the present invention. In FIG. 2, the same reference numerals as in FIG. 1 denote the same members.

Hereinafter, in the description of FIG. 2, contents overlapping with that of FIG. 1 are not described again, and only differences are described.

The flexible metal laminate 100 of FIG. 1 has a cross-sectional structure in which an alloy layer 10 is disposed on one surface of the insulating film 20, whereas the flexible metal laminate 110 according to FIG. 2 is an insulating film ( 20) has a double-sided structure in which an alloy layer 10 is disposed on the upper and lower surfaces thereof, respectively.

Here, although the plurality of alloy layers 10 are indicated by the same reference numerals, they may be the same or different from each other. For example, the plurality of alloy layers 10 may have different alloy compositions or may have different resistivity, resistance change rates for each temperature, thickness, and the like. It is the same as that of FIG. 1 except that the two alloy layers 10 are introduced, and individual descriptions thereof will be omitted.

3 schematically shows a cross-sectional structure of a flexible metal laminate 120 according to another embodiment of the present invention. In FIG. 3, the same reference numerals as in FIGS. 1 to 2 denote the same members.

Hereinafter, in the description of FIG. 3, contents overlapping with those of FIGS. 1 to 2 are not described again, and only differences are described.

The flexible metal laminates 100 and 110 of FIGS. 1 and 2 have a structure in which the alloy layer 10 is directly disposed on one or both sides of the insulating film 20, whereas the flexible metal laminate 120 according to FIG. 3 is an insulating film. It has a double-sided structure in which the alloy layer 10 is disposed on the upper and lower surfaces of the upper and lower surfaces of the center 20, and an adhesive layer 40 is further included therebetween.

The adhesive layer 40 exhibits adhesion between the adjacent insulating film 20 and the alloy layer 10, heat resistance, and interlayer adhesion.

The adhesive layer 40 may be used without limitation, a conventional thermosetting adhesive component known in the art, for example, a thermosetting resin; And it may be formed from an adhesive composition comprising at least one selected from the group consisting of a thermoplastic resin, a curing agent and an inorganic filler.

Non-limiting examples of thermosetting resins that can be used include epoxy resins, polyurethane resins, phenolic resins, melamine resins, silicone resins, urea resins, vegetable oil-modified phenolic resins, xylene resins, guanamine resins, diallylphthalate resins, vinyl esters. It may be one or more selected from the group consisting of resins, unsaturated polyester resins, furan resins, polyimide resins, cyanate resins, maleimide resins, and benzocyclobutene resins. Specifically, it is an epoxy resin, a phenol resin, a melamine resin, a silicone resin, a urethane resin, or a urea resin, preferably a halogen-free thermosetting adhesive.

Double epoxy resin is preferable because of its excellent reactivity and heat resistance, and more preferably, it is a non-halogen-based epoxy resin that does not contain halogen elements such as bromine (Br) in the molecule. The epoxy resin may use a conventional epoxy resin known in the art without limitation, and it is preferable that two or more epoxy groups are present while not including a halogen element in one molecule. Non-limiting examples of usable epoxy resins include bisphenol A/F/S type resins, novolac type epoxy resins, alkylphenol novolac type epoxy resins, polyfunctional phenol novolak type epoxy resins, biphenyl type, Aralkyl (Aralkyl) type, naphthol (Naphthol) type, dicyclopentadiene type, or a mixture thereof.

More specific examples include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, naphthalene type epoxy resin, anthracene epoxy resin, biphenyl type epoxy resin, tetramethyl biphenyl type epoxy resin, phenol novolac Type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol S novolac type epoxy resin, biphenyl novolac type epoxy resin, naphthol novolac type epoxy resin, naphthol phenol co-condensed novolac type epoxy resin , Naphthol Koresol co-condensed novolak type epoxy resin, aromatic hydrocarbon formaldehyde resin modified phenol resin type epoxy resin, triphenyl methane type epoxy resin, tetraphenylethane type epoxy resin, dicyclopentadiene phenol addition reaction type epoxy resin, phenol arral And a kill type epoxy resin, a polyfunctional phenol resin, and a naphthol aralkyl type epoxy resin. At this time, the above-described epoxy resin may be used alone or two or more types may be used in combination.

The content of the thermosetting resin is not particularly limited, and for example, may be 30 to 70 parts by weight based on the total weight (eg, 100 parts by weight) of the adhesive composition, and preferably 40 to 65 parts by weight. When it has the above-described content range, sufficient adhesion and excellent heat resistance can be secured.

The adhesive layer 40 according to the present invention further contains a thermoplastic resin, thereby improving adhesiveness, improving flexibility, and reducing thermal stress.

As the thermoplastic resin, conventional thermoplastic resins, thermoplastic rubbers, or both known in the art may be used. Non-limiting examples of thermoplastic resins that can be used include acrylonitrile-butadiene rubber (NBR), styrene butadiene rubber (SBR), acrylonitrile-butadiene-styrene rubber (ABS), carboxyl-terminated butadiene acrylonitrile rubber. (CTBN), polybutadiene, styrene-butadiene-ethylene resin (SEBS), acrylic acid and/or methacrylic acid having a side chain of 1 to 8 carbon atoms Ester resin (acrylic rubber), or a mixture of one or more of them. Preferably, it may be an acrylic rubber.

It is preferable that the above-described thermoplastic resin, specifically rubber, contains a functional group capable of reacting with an epoxy resin which is a thermosetting resin. For a specific example, it is at least one functional group selected from the group consisting of an amino group, a carboxyl group, an epoxy group, a hydroxyl group, a methoxy group, an isocyanate group, a vinyl group, and a silanol group. Since such a functional group forms a strong bond with the epoxy resin, heat resistance is improved after curing, which is preferable. In particular, in the present invention, it is more preferable to use an acrylonitrile-butadiene copolymer (NBR) in consideration of adhesiveness, flexibility, and relaxation effect of thermal stress. It is more preferable to contain a carboxyl group as a functional group capable of reacting.

The content of the thermoplastic resin is not particularly limited, and for example, may be 1 to 35 parts by weight based on the total weight of the adhesive composition, and preferably 5 to 30 parts by weight. If it is out of the above range, sufficient adhesiveness may not be obtained, and heat resistance may be lowered.

For example, the content of the polymer resin constituting the adhesive layer 40 may be 50 to 90 parts by weight, preferably 60 to 90 parts by weight based on the total weight (eg, 100 parts by weight) of the adhesive layer. It may be 85 parts by weight. When a thermosetting resin and a thermoplastic resin are mixed as the polymer resin, the mixing ratio of the thermosetting resin and the thermoplastic resin may be 20 to 80: 80 to 20 weight ratio based on 100 parts by weight of the polymer resin, and preferably 50 ~80: It may be a 20-50 weight ratio.

In the present invention, a conventional curing agent known in the art may be used without limitation, and may be appropriately selected and used according to the type of epoxy resin to be used. Non-limiting examples of the curing agent that can be used include imidazole-based, phenol-based, anhydride-based, dicyanamide-based, and aromatic polyamine curing agents. Non-limiting examples of the curing agent that can be used include phenolic curing agents such as phenol novolac, cresol novolac, bisphenol A novolac, and naphthalene type; There are polyamine-based curing agents such as metaphenylenediamine, diaminodiphenylmethane (DDM), and diaminodiphenylsulfone (DDS), and these may be used alone or in combination of two or more. The content of the curing agent is not particularly limited, and may be, for example, 0.1 to 10 parts by weight based on the total weight (100 parts by weight) of the adhesive composition.

In addition, the epoxy resin composition of the present invention may further include a curing accelerator to increase the curing reaction rate. Such a curing accelerator is not particularly limited as long as it is a material known in the art, but non-limiting examples include tertiary amines such as benzyldimethylamine, triethanolamine, triethylenediamine, dimethylaminoethanol, and tri(dimethylaminomethyl)phenol; Imidazole series such as 2-methylimidazole and 2-phenylimidazole; Organic phosphine series such as triphenylphosphine, diphenylphosphine, and phenylphosphine; And tetraphenyl boron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphine tetraphenylborate. The content of the curing accelerator included in the epoxy resin composition is not particularly limited, but considering curability, etc., the curing accelerator is preferably included in an amount of 0.001 to 0.5 parts by weight based on 100 parts by weight of the total of the thermosetting resin and the curing agent.

In the present invention, conventional inorganic fillers known in the art may be included. Non-limiting examples of the inorganic fillers that can be used include silicas such as natural silica, fused silica, amorphous silica, crystalline silica, and the like; Boehmite, alumina, aluminum hydroxide [Al(OH) ₃ ], talc, spherical glass, calcium carbonate, magnesium carbonate, magnesia, clay, calcium silicate, titanium oxide, antimony oxide, glass fiber, boric acid Aluminum, barium titanate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, calcium zirconate, boron nitride, silicon nitride, talc, mica, and the like. These inorganic fillers may be used alone or in combination of two or more.

The size of the inorganic filler is not particularly limited, and the average particle diameter may range from 0.5 to 10 μm. In addition, the content of the inorganic filler is not particularly limited, and may be, for example, 0 to 35 parts by weight based on the total weight (100 parts by weight) of the adhesive composition, and specifically 5 to 30 parts by weight.

The adhesive layer 40 according to the present invention may further include at least one of a silane coupling agent, a dispersant, a flame retardant filler, and a curing accelerator.

A silane coupling agent known in the art may be used without limitation, and is preferably a silane coupling agent having an epoxy group. Non-limiting examples of the epoxy group silane coupling agent that can be used include 3-(glycidyloxy)propyl)trimethoxysilane, 3-(glycidyloxy)propyltriethoxysilane, 2-(3,4-epoxy Cyclohexyl)ethyl trimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl triethoxysilane, epoxypropoxypropyl trimethoxysilane, or mixtures thereof. The content of the silane coupling agent is not particularly limited, for example, it may be more than 0, 5 parts by weight or less based on the total 100 parts by weight of the adhesive layer 40, preferably 0.3 to 1.5 parts by weight.

The dispersant plays a role of dispersing each of the materials constituting the composition for forming an adhesive layer and preventing reaggregation by maintaining a distance to express the uniform physical properties of the electromagnetic wave absorbing layer. The dispersant may be a conventional one known in the art, and examples include a high molecular weight block copolymer type dispersant. It is preferable to use a wettable dispersant that can further improve the dispersibility of the mixed inorganic filler. The usable wetting dispersant is not particularly limited as long as it is a conventional dispersion stabilizer used in the paint field, and examples include BYK's Disperbyk-110, 111, 161, 180, and the like. The content of the dispersant is not particularly limited, and for example, may be greater than 0, 5 parts by weight or less, and preferably 0.1 to 2 parts by weight based on 100 parts by weight of the adhesive layer 40.

In addition, in the present invention, in order to impart flame retardancy to the adhesive layer 40, at least one flame retardant filler may be further included. Here, the kind of flame retardant filler is not particularly limited, but due to the addition of the flame retardant filler, the flexible metal laminate 120 according to the present invention is to impart flame retardancy that passes the vertical combustion test (VW-1 test) of the UL standard. desirable.

More specifically, as the flame retardant filler, at least one selected from the group consisting of halogen flame retardants, phosphorus-based flame retardants, nitrogen-based flame retardants, metal-based flame retardants, and antimony-based flame retardants may be used. Among them, halogen-based flame retardants such as bromine-based flame retardants and chlorine-based flame retardants and phosphorus-based flame retardants are preferred, and phosphorus-based flame retardants are more preferred. The content of the flame retardant filler is not particularly limited, and as an example may range from 5 to 30 parts by weight, preferably 5 to 15 parts by weight, more preferably 5 to 10 parts by weight, based on the total weight of the adhesive layer 40. have. When included in the above-described content, sufficient flame retardancy may be imparted to the adhesive layer 40, and excellent flexibility and elongation may be exhibited.

In one embodiment of the present invention, the thermosetting adhesive composition constituting the adhesive layer 40 includes 30 to 70 parts by weight of a non-halogen-based epoxy resin based on 100 parts by weight of the composition; 1 to 35 parts by weight of a thermoplastic resin; 0.1 to 10 parts by weight of a curing agent (additive); And 0 to 30 parts by weight of an inorganic filler. Here, the epoxy resin can implement chemical resistance and flexibility, and the thermoplastic resin improves adhesion and flexibility, and exhibits thermal stress relaxation effects. In this case, the thermosetting adhesive composition may include an organic solvent, and the amount of the organic solvent may be in a range of the remaining amount to match the total 100 parts by weight of the composition.

In addition to the above-described components, the present invention provides a flame retardant generally known in the art as needed, other thermosetting resins or thermoplastic resins not described above, and oligomers thereof, as long as the intrinsic properties of the adhesive layer 40 are not impaired. Various polymers, solid rubber particles or ultraviolet absorbers, silane coupling agents, antioxidants, polymerization initiators, dyes, pigments, thickeners, leveling agents, antioxidants, masking agents, lubricants, processing stabilizers, plasticizers, foaming agents, reinforcing agents, coloring agents, fillers, Other additives such as granules, metal inert agents, and the like may be further included.

The thickness of the adhesive layer 40 is not particularly limited, and may be, for example, 5 to 30 µm, and preferably 10 to 20 µm.

The flexible metal laminates 100, 110, and 120 of the present invention composed of the three embodiments described above contain copper (Cu) and nickel (Ni) as active ingredients on one or both sides, respectively, with the insulating film 20 as the center. By providing at least a binary or more alloy layer (alloy), a high specific resistance of the alloy layer, a field requiring heat generation by using a low resistance change rate according to temperature, for example, a flexible metal composite substrate of an optical module for optical communication It can be applied to the application. The heating temperature is not particularly limited, for example, the average operating temperature (maintenance temperature) is 65 ℃ ± 10%, the maximum temperature may be 120 ℃ or less, specifically 85 to 105 ℃.

According to one embodiment of the present invention, the adhesive strength (peel stregth) value of the insulating film 20 to the alloy layer 10 in the flexible metal laminate 100 is 0.5 kgf / cm or more, preferably 0.8 to 1.2 kgf May be /cm. Here, the value of Peel Strength means that the value was measured according to the IPC-TM-650 2.4.9 standard.

Meanwhile, in the present invention, the embodiments shown in FIGS. 1 to 3 described above are exemplarily described. However, it is also within the scope of the present invention to freely select and configure the number of layers constituting the flexible metal laminates 100, 110, and 120 and the order of stacking them according to the purpose. For example, the order of each of the layers 10, 20, and 40 may be changed, or other layers conventional in the art may be introduced to have a multilayer structure than the illustrated structure.

<Method of manufacturing a flexible metal laminate>

Hereinafter, a method of manufacturing a flexible metal laminate according to an embodiment of the present invention will be described. However, it is not limited only by the following manufacturing method, and the steps of each process may be modified or selectively mixed and performed as necessary.

The flexible metal laminate according to the present invention may be manufactured without limitation according to a conventional method known in the art, and may largely have the following three embodiments.

The first embodiment of manufacturing the flexible metal laminate is to use a thermocompression lamination process.

6 and 7 schematically illustrate a manufacturing process of the flexible metal laminates 100 and 110 according to an embodiment of the present invention, and as an example, FIG. 6 is a cross-sectional flexible metal laminate using a lamination process ( 100) is a manufacturing process diagram, and FIG. 7 is a manufacturing process diagram of the double-sided flexible metal laminate 110 using a lamination process.

As a specific example of manufacturing a double-sided flexible metal laminate with reference to FIGS. 6 to 7, (i) preparing two metal substrates made of at least a binary or higher alloy; And (ii) lamination after interposing an insulating film between the two metal substrates.

The insulating film may be a polyimide film or a polyimide film coated with a thermoplastic polyimide layer. In addition, the polyimide film or the thermoplastic polyimide layer may be pre-cured or completely cured, respectively. In this case, when using a pre-cured polyimide film, the adhesion between the polyimide film and the metal substrate may be further increased during the manufacture of a single-sided or double-sided flexible metal laminate.

Here, the temporary curing refers to a state that has already been cured through a curing process to a certain level or more, that is, a pre-cured state. For example, the degree of cure (D) may be about 40% to 80%. In addition, complete curing means a state in which the degree of curing is 80% or more, preferably 80 to 100%.

Next, after interposing an insulating film between two alloy substrates, a thermocompression bonding lamination process is performed.

The compression process conditions can be appropriately adjusted within a conventional range known in the art. For example, thermocompression Lami. Conditions during the process (roll-to-roll) ^{may be performed under conditions of a temperature of 200 to 400° C., a pressure of 3 to 200 kgf/cm 2} , and a compression speed of 0.1 m/min to 10 m/min, and under an inert gas atmosphere such as nitrogen. Can be implemented. However, it is not particularly limited thereto. When performing the compression (lamination) process under such a low temperature condition, excellent adhesion properties and appearance properties can be secured.

If necessary, a heat treatment process may be performed after the compression process. These heat treatment conditions are not particularly limited, and may be appropriately performed within conditions known in the art.

Here, the alloy substrate and the insulating film (eg, polyimide film) may each be in a sheet shape, or the roll-shaped alloy substrate and the insulating film (eg, polyimide film) are used in a roll-to-roll method. Accordingly, it may be continuously laminated and then wound in a roll shape. When such a roll-to-roll continuous production method is applied, it is possible to simplify the manufacturing process and reduce the process cost due to an increase in yield. In addition, sheet-to-sheet lamination, roll-to-sheet lamination, or the like may be used.

A second embodiment of manufacturing a flexible metal laminate according to the present invention is to use a casting method.

8 and 9 schematically illustrate a manufacturing process of the flexible metal laminates 100 and 110 according to an embodiment of the present invention, and as an example, FIG. 8 is a cross-sectional flexible metal laminate using a casting method ( 100) is a manufacturing process diagram, and FIG. 9 is a manufacturing process diagram of a double-sided flexible metal laminate 110 using a casting method.

As a specific example of manufacturing a double-sided flexible metal laminate with reference to FIGS. 8 to 9, (i) drying after applying a polyimide solution on one surface of at least a binary or higher alloy substrate (eg, a first metal substrate) Thereby forming a polyimide coating layer; And (ii) placing one surface of the alloy substrate on which the polyimide coating layer is formed and at least a binary or higher alloy substrate (eg, a second metal substrate) in contact with each other, and then bonding them.

The method of applying the polyimide solution on the alloy substrate may be a casting method, but is not particularly limited thereto, and a conventional coating method known in the art may be used without limitation. For example, various methods such as dip coating, die coating, roll coating, slot die, comma coating, or a mixture thereof may be used. The drying process may be appropriately performed within conventional conditions known in the art, and for example, may be performed at 80 to 250°C.

Thereafter, the curing process may be appropriately performed within a conventional range known in the art, and may be performed under a temperature condition of 200 to 400°C. If necessary, the cured product may be subjected to plasma surface treatment and then slit.

Subsequently, the cured result may be subjected to a thermocompression bonding process through a lamination process including a heating roll. Alternatively, the curing process and the thermocompression process may be simultaneously performed through a lamination process including a heating roll having the above-described curing temperature condition.

Meanwhile, in the present invention, the application of the polyimide solution on one alloy substrate has been described in detail. However, it is also within the scope of the present invention to apply a polyimide solution to both alloy substrates, arrange them opposite to each other, and then thermocompressively form a flexible metal laminate.

A third embodiment of manufacturing a flexible metal laminate according to the present invention is to use a batch cure process.

10 schematically shows a manufacturing process of a flexible metal laminate 120 according to another embodiment of the present invention.

As a specific example of manufacturing the double-sided flexible metal laminate 120 with reference to FIG. 10, (i) applying an adhesive composition on one or both sides of a polyimide film and drying to form an adhesive layer; (ii) a polyimide film having an adhesive layer formed therebetween may be interposed between the two metal substrates to be compressed and then cured.

The adhesive composition is not particularly limited, and a thermosetting adhesive composition known in the art may be used. For example, it may include at least one of a thermosetting resin, a thermoplastic resin, a curing agent, and an inorganic filler. For example, the thermosetting adhesive composition, based on 100 parts by weight of the composition, 30 to 70 parts by weight of a non-halogen-based epoxy resin; 1 to 35 parts by weight of a thermoplastic resin; 0.1 to 10 parts by weight of a curing agent (additive); And 0 to 30 parts by weight of an inorganic filler. If necessary, at least one of a silane coupling agent, a dispersant, a flame retardant filler, and a curing accelerator may be further included.

Then, a thermosetting adhesive composition is applied on the prepared polyimide film and then dried.

A method of applying the thermosetting adhesive composition onto the polyimide film is not particularly limited, and a conventional coating method known in the art may be used without limitation. For example, various methods such as casting method, dip coating, die coating, roll coating, slot die, comma coating, or a mixture thereof may be used. The drying process may be appropriately performed within conventional conditions known in the art. For example, drying may be performed at 60 to 200°C. The dried thermosetting adhesive composition (adhesive layer) may be pre-cured or semi-cured. In the case of using the adhesive layer in the uncured state as described above, the adhesion between the polyimide film and the metal substrate (alloy layer) can be further increased during the manufacture of the double-sided flexible metal laminate afterwards.

Subsequently, after the adhesive layer formed on the polyimide film and the two alloy substrates are disposed so as to face each other to perform a pressing process, this is wound in a roll shape and post-cured in a batch type in a heating oven. At this time, after compressing the adhesive layer and one alloy substrate, another alloy substrate is sequentially opposed to each other and post-curing to constitute a flexible metal laminate is also within the scope of the present invention.

The conditions of the compression process and the post-curing process are not particularly limited, and can be appropriately adjusted within a conventional range known in the art.

<Flexible metal composite substrate>

According to an embodiment of the present invention, a flexible metal composite substrate provided with the aforementioned flexible metal laminate is provided.

Here, the flexible metal composite substrate may refer to a flexible metal printed circuit board (FPCB), and may have a structure in which a coverlay film (CL) is stacked on at least one or more circuit patterns.

4 to 5 are cross-sectional views schematically showing the structure of a flexible metal composite substrate 200 and 210 according to an embodiment of the present invention. As an example, FIG. 4 is a flexible metal including one flexible metal laminate 110 It is a cross-sectional view of the composite substrate 200, and FIG. 5 is a cross-sectional view of a flexible metal composite substrate 210 including two flexible metal laminates 100 and 110.

In FIG. 4, the same reference numerals as in FIGS. 1 to 3 denote the same members. At this time, each member 10, 20, 40, 50, 150 indicated by the same reference numeral may have the same or different configurations, and for convenience, they are described as first and second. Hereinafter, in the description of FIG. 4, contents overlapping with those of FIGS. 1 to 3 will not be described again, and only differences will be described.

Referring to FIG. 4, the flexible metal composite substrate 200 of the present invention has a structure in which one flexible metal laminate 110 is disposed between two coverlay films 150, and these are integrated. Specifically, a first coverlay film 150 including a first polymer film 50 and a first adhesive layer 60; A second coverlay film 150 including a second polymer film 50 and a second adhesive layer 60; And a flexible metal laminate 110 interposed between the first adhesive layer 60 of the first coverlay film 150 and the second adhesive layer 60 of the second coverlay film 150 do.

The flexible metal laminate 110 disposed between the two coverlay films 150 includes: (i) an insulating film 20; And a single-sided flexible metal laminate on which the first alloy layer 10 is laminated; Or (ii) a first alloy layer 10; Insulating film 20; And a double-sided flexible metal laminate on which the second alloy layer 10 is laminated. Preferably, it may be a double-sided flexible metal laminate 110.

Specifically, the first alloy layer 10 positioned on one surface of the flexible metal laminate 110 of FIG. 4 is disposed between the first adhesive layer 60 and the insulating film 20 of the first coverlay film 150 The second alloy layer 10 is disposed between the insulating film 20 and the second adhesive layer 60 of the second coverlay film 150, and may have a structure in which they are integrally laminated.

In the flexible metal laminate 110, at least one of the first alloy layer 10 and the second alloy layer 10, or all of them 10, is a circuit pattern part through conventional dry or wet etching known in the art. Can be formed. Although not shown in FIG. 4, in the flexible metal laminate 100, at least one of the first alloy layer 10 and the second alloy layer 10, specifically, the first alloy layer 10 and the second alloy layer 10 ) May have at least one layer of circuit patterns each having a predetermined area, line width, and shape. In particular, it is preferable that a circuit pattern layer and a photo solder resist (PSR) layer that insulate the circuit layer are formed.

In addition, although not shown in FIG. 4, the flexible metal composite substrate 200 includes at least one through hole (not shown) penetrating the first coverlay film 150 and the second coverlay film 150, It may have a structure electrically conductive through the through hole.

In addition, the first coverlay film 150 and the second coverlay film 150 are the same or different from each other, and each independently refers to a composite film coated with an adhesive on a polymer film, or a release film in addition thereto. The coverlay film 150 is in close contact with the first alloy layer 10 and the second alloy layer 10 positioned on the upper and lower surfaces of the flexible copper clad laminate 110, and specifically etched flexible printed circuit board (FPCB) It is used to protect and insulate the exposed circuit pattern. It also plays a role in preventing cracks from occurring.

The first coverlay film 150 and the second coverlay film 150 may have a conventional configuration known in the art, and specifically, a polymer film 50 and an adhesive layer 40 are sequentially stacked. It may be a multi-layered structure.

The first polymer film 50 and the second polymer film 50 are base films of the coverlay film 150.

Each of the first and second polymer films 50 may use conventional polymers used in the coverlay field, and may be the same as or different from each other. Non-limiting examples of usable polymer films include, for example, one or more selected from the group consisting of polyimide, polyester, polyphenylene sulfide, polyester sulfone, polyetherether ketone, aromatic polyamide, polycarbonate, and polyarylate. It may include. Preferably it is a polyimide (PI) film. The thickness of the first and second polymer films 50 is not particularly limited, and may be, for example, 5 to 125 µm, and preferably 7.5 to 25.0 µm.

In addition, the first and second adhesive layers 60 may be formed on the other surface of the first and second polymer films 50, for example, a polyimide (PI) layer to have a predetermined thickness.

The first and second adhesive layers 60 may use conventional adhesives known in the art, and may contain, for example, an acrylic adhesive, a silicone adhesive, an epoxy adhesive, or a mixture thereof. In addition, the thickness of the first and second adhesive layers 60 is not particularly limited, and may be 5 to 30 μm as an example, and preferably 10 to 20 μm.

On the surfaces of the above-described first and second adhesive layers 60, that is, non-contact surfaces that do not come into contact with the first and second polymer films 50, a release layer to protect the first and second adhesive layers 50 (Not shown) may be attached.

Such a release layer may be a conventional one known in the art, for example, may be any one of a release paper (release paper), and a release polymer film (eg, a release PET film). This release layer may be formed by laminating. The release polymer film may be applied without limitation, such as a conventional plastic film known in the art. Non-limiting examples of plastic films that can be used include polyester films such as polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate, polyethylene films, polypropylene films, cellophane, diacetylcellulose films, and triacetylcellulose films. , Acetylcellulose butyrate film, polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, polymethylpentene film, polysulfone film, polyether Turketone film, polyethersulfone film, polyetherimide film, polyimide film, fluororesin film, polyamide film, acrylic resin film, norbornene resin film, cycloolefin resin film, and the like. These plastic films may be transparent or semitransparent, may be colored, or may be non-colored, and may be appropriately selected depending on the application.

The flexible metal composite substrate 200 according to the present invention may be manufactured according to a conventional method known in the art. For example, a flexible metal laminate 110 including a circuit pattern of one or more layers; And coverlay films 150 disposed on both sides of the flexible metal laminate 110 are sequentially laminated and then thermally compressed.

Specifically, on at least one side of the flexible metal laminate 110, specifically on at least one layer of circuit patterns formed on both sides, the first adhesive layer 60 and the second coverlay film of the first coverlay film 150 ( The second adhesive layers 60 of 150) are disposed to face each other and then bonded to form a laminate. At this time, when the first and second coverlay films 150 include release films, the release films are detached and then bonded to the flexible metal laminate 110.

After configuring the laminate as described above, heat and/or pressure are applied to perform thermal compression bonding. At this time, the thermocompression bonding conditions are not particularly limited, and as an example, after configuring the above-described laminate, thermocompression bonding may be performed under the conditions of ^{a temperature of about 130 to 180° C., a pressure of 5 to 60 kgf/cm 2, and 50 to 180 minutes.}

5 schematically shows a cross-sectional structure of a flexible metal composite substrate 210 according to another embodiment of the present invention.

In FIG. 5, the same reference numerals as those of FIGS. 1 to 4 denote the same members. Hereinafter, in the description of FIG. 5, content overlapping with FIGS. 1 to 4 will not be described again, and only differences will be described.

While the flexible metal composite substrate 210 of FIG. 4 has a structure in which one double-sided flexible metal laminate 110 is disposed between two coverlay films 150 and they are integrally laminated, the flexible metal composite of FIG. 5 In the substrate 210, two flexible metal laminates, specifically one single-sided flexible metal laminate 100 and one double-sided flexible metal laminate 110 are disposed between the two coverlay films 150, and they are integrally laminated. Shows the structure. That is, the ductile metal composite substrate 200 of FIG. 4 includes the alloy layer 10 of two layers (2L), whereas the ductile metal composite substrate 210 of FIG. 5 includes the alloy layer 10 of three layers (3L). ).

Referring to FIG. 5, the flexible metal composite substrate 210 of the present invention comprises: a first coverlay film 150; A single-sided flexible metal laminate 100; Double-sided flexible metal laminate 110; And the second coverlay film 150 is laminated, the adhesive disposed between the insulating film 20 of the single-sided flexible metal laminate 100 and the first alloy layer 10 of the double-sided flexible metal laminate 110 It further includes a layer (70).

Specifically, the alloy layer 10 positioned on one side of the single-sided flexible metal laminate 100 of FIG. 5 is the insulating property of the first adhesive layer 60 and the single-sided flexible metal laminate 100 of the first coverlay film 110. The first alloy layer 10 disposed between the films 20 and positioned on one side of the double-sided flexible metal laminate 100 is between the adhesive layer 70 and the insulating film 20 of the double-sided flexible metal laminate 110. The second alloy layer 10 is disposed on the other surface of the double-sided flexible metal laminate 110 and the second adhesive layer 60 of the second coverlay film 150 and the double-sided flexible metal laminate 110 have insulation properties. It is disposed between the films 20 and has an integrated structure thereof.

Here, the adhesive layer 70 may be a conventional adhesive known in the art, and is not particularly limited. As an example, the adhesive layer 40 provided on the above-described flexible metal laminate 120 or the 1-2 adhesive layer 60 provided on the coverlay film 150 may have the same or different configurations, respectively. .

On the other hand, in the present invention, it is specifically exemplified to manufacture the flexible metal composite substrates 200 and 210 including the above-described alloy layer 10 in two layers (2L) or three layers (3L). However, the present invention is not limited thereto, and manufacturing by diversifying the number of alloy layers 10 included in the flexible metal composite substrate, the number of layers, shapes, and structures of the circuit pattern is also within the scope of the present invention.

The flexible metal composite substrate 200 and 210 of the present invention constructed as described above is an optical communication system used in optical communication systems such as an optical data link using light as an information transmission medium or an optical local area network. It can be applied as a heat generating printed circuit board for optical modules. These flexible metal composite substrates (200, 210) exhibits self-heating characteristics when an external voltage is applied, and stably exhibits such heating characteristics to continuously maintain a predetermined operating temperature (eg, 65°C±10%), Signal loss due to amplification of optical communication radio waves can be minimized. In addition, it can be applied to security systems, electric fields (cameras, etc.), and medical uses, and can be applied to various electronic and communication devices that require heat generation.

Hereinafter, the present invention will be described in detail through Examples, but the following Examples and Experimental Examples are only illustrative of one embodiment of the present invention, and the scope of the present invention is not limited to the following Examples and Experimental Examples.

[Example 1]

1-1. Fabrication of single-sided flexible metal laminates

Insulating film (polyimide film coated with a thermoplastic polyimide layer, 25 μm) and copper-nickel alloy substrate (thickness: 12 Μm) was bonded at 350°C using a laminator to prepare a single-sided flexible metal laminate.

1-2. Manufacturing of double-sided flexible metal laminates

An insulating film (a polyimide film coated with a thermoplastic polyimide layer, 25 µm) was applied to two copper-nickel alloy substrates (thickness: 12). ㎛), then using a laminator 350 Bonding at °C to prepare a flexible metal laminate.

[Comparative Example 1]

A single-sided or double-sided flexible copper-clad laminate of Comparative Example 1 was manufactured in the same manner as in Example 1, except that copper foil having the same thickness was used instead of the copper-nickel alloy substrate.

[Experimental Example 1. Evaluation of surface properties of alloy layer]

In order to evaluate the surface properties of the copper-nickel alloy substrate and the copper substrate, an electron microscope (SEM, 6,000 magnification) was used.

FIG. 11 is an SEM photograph showing the surface of a copper-nickel binary alloy substrate, and FIG. 12 is a SEM photograph showing the surface of a copper substrate. It was found that the copper substrate had roughness of approximately 3 μm or less, whereas the binary Cu-Ni alloy substrate had a flat surface with little roughness (see FIGS. 11 to 12 below).

[Experimental Example 2. Evaluation of Electrical Properties of Alloy Layer]

Using a copper-nickel alloy substrate and a copper substrate, the specific resistance characteristics and the resistance characteristics according to the temperature change were measured, respectively, and the results are shown in Table 1 and FIG. 13 below.

At this time, the specific resistance value was measured according to the IPC-TM-650 2.5.17 evaluation method.

As a result of the experiment, it was found that the copper-nickel alloy layer has a specific resistance that is approximately 29.2 times higher than that of the copper layer.

In addition, for both ends of the line of the sample prepared by processing the line circuit on the flexible laminated metal plate, the resistance to the line was measured by increasing the temperature from room temperature to 210°C in a high-temperature oven, and measuring the resistance for each temperature section.

As a result of checking the resistance change according to temperature, it was found that the resistance value of the copper-nickel alloy layer was at least 10 times higher than that of the copper layer over room temperature and high temperature regions (eg, 30 to 200°C). In particular, the resistance value of the alloy layer at 30°C was 26.78 times that of copper foil, 21.93 times at 100°C, 19.51 times at 150°C, and 16.90 times at 200°C. In addition, as a result of checking the rate of change in resistance in a predetermined temperature (eg, 50-100° C.), the resistance of the copper layer increases as the temperature increases, whereas the resistance of the alloy layer increases without change. It was confirmed that it was maintained (see FIG. 13 below).

Therefore, it was confirmed that the alloy layer according to the present invention has a high specific resistance difference in the room temperature and high temperature region, and a low resistance change rate according to temperature, so that it can be applied for heat generation.

Alloy layer Copper layer Thickness (㎛) 12 μm 12 μm content 56% Cu + 44% Ni 100% Cu Resistivity (Ω·m) 49.0 × 10 ^-8 1.68×10 ^-8 According to the temperature (50-100℃)
Resistance change rate (%/℃) 0.001 14 Patterning method FPCB Pattering Available FPCB Pattering Available

[Experimental Example 3]

The properties of the flexible metal laminates prepared in Example 1 and Comparative Example 1 were measured according to the following measuring method, and the results are shown in Table 2 below. At this time, the measurement method and required physical properties of each evaluation item are shown in Table 2 below.

Item Required properties Example 1 Comparative Example 1 Assessment Methods Flame retardant VTM-0 VTM-0 VTM-0 UL 94 Adhesion
(Peel Strength, alloy layer) 0.5 kgf/cm 1.1 - IPC-TM-650 2.4.9 Adhesion
(Peel Strength, copper layer) 0.7 kgf/cm - 1.3 IPC-TM-650 2.4.9 Heat resistance
(Solder Floating) 288℃ × 10 sec Pass Pass IPC-TM-650 2.4.13 Dimensional stability (after etching)
(MD/TD) 0.1% -0.01/-0.02 -0.01/-0.01 IPC-TM-650 2.2.4 Surface resistance (@PI, Ω) 1×10 ⁶ 1×10 ¹⁴ 1×10 ¹⁴ IPC-TM-650 2.5.5.3 Permittivity (@1MHz) <3.5 3.2 3.2 IPC-TM-650 2.5.5.3 Dielectric coefficient (@1MHz) <0.01 0.005 0.005 The tensile strength
(Tensile strength, MPa) 150 MPa 175 180 IPC-TM-650 2.4.19 Elongation (%) 50% 95 100 Moisture absorption
(Moisture absorption, %) <2.0% 1.1 1.1 IPC-TM-650 2.6.2

As a result of the experiment, it was confirmed that the flexible metal laminate of the present invention provided with a copper-nickel alloy layer had physical properties equivalent to that of a general flexible metal laminate provided with copper foil in all evaluation items.

100, 110, 120: flexible metal laminate
10: alloy layer
20: insulating film
40: adhesive layer
150: coverlay film
50: polymer film
60: first adhesive layer, second adhesive layer
70: adhesive layer
200, 210: flexible metal composite substrate

Claims (21)

Insulating film; And
It is disposed on one or both sides of the insulating film, at least a binary or more alloy layer containing copper and nickel; includes,
The specific resistance value of the alloy layer is 2.0 × 10 ^-8 Ω·m or more,
A flexible metal laminate having a resistance change rate of 0.05%/°C or less by temperature at 50 to 100°C. The method of claim 1,
The alloy layer,
A binary alloy containing copper and nickel;
A ternary alloy containing copper, nickel, and a first metal (M _{1 );} or
A flexible metal laminate comprising a quaternary alloy containing copper, nickel, a first metal (M ₁ ) and a second metal (M _{2 ).} The method of claim 2,
In the binary alloy, the alloy ratio of copper and nickel is 54 to 58: 46 to 42 weight ratio of a flexible metal laminate. The method of claim 2,
The first metal (M ₁ ) included in the ternary alloy is any one of Mn, Fe, Al, and C. A flexible metal laminate. The method of claim 2,
In the ternary alloy, the alloy ratio of copper, nickel, and the first metal (M ₁ ) is 53.9-56.5: 46-42: 0.1-1.5 weight ratio of a flexible metal laminate. The method of claim 2,
The second metal (M ₂ ) included in the quaternary alloy is any one of Mn, Fe, Al, and C, and is different from _{the first metal (M 1 ).} The method of claim 2,
In the quaternary alloy, the alloy ratio of copper, nickel, the first metal (M ₁ ) and the second metal (M ₂ ) is 53.8 to 56.5: 46 to 41: 0.1 to 1.5: 0.1 to 1.0 weight ratio. The method of claim 1,
The thickness of the alloy layer is 12 to 35 ㎛, flexible metal laminate. The method of claim 1,
The surface roughness (Rz) of the alloy layer is 1.0 μm or less, a flexible metal laminate. The method of claim 1,
The insulating film is a polyimide film, or a flexible metal laminate of a polyimide film coated with a thermoplastic polyimide layer. The method of claim 10,
Each of the polyimide film or the thermoplastic polyimide layer further comprises at least one of a colorant and an inorganic filler. The method of claim 11,
The polyimide is a transparent polyimide, a colored polyimide, or a black polyimide, a flexible metal laminate. The method of claim 1,
A flexible metal laminate further comprising an adhesive layer disposed between the insulating film and the alloy layer. The method of claim 1,
A flexible metal laminate having a Peel stregth value of 0.5 kgf/cm or more of the insulating film to the alloy layer measured according to IPC-TM-650 2.4.9. A first coverlay film including a first polymer film and a first adhesive layer; And
A second coverlay film including a second polymer film and a second adhesive layer; And
The flexible metal laminate according to any one of claims 1 to 14, disposed between the first coverlay film and the second coverlay film;
Flexible metal composite substrate comprising a. The method of claim 15,
The flexible metal laminate,
(i) an insulating film; And a single-sided flexible metal laminate on which the first alloy layer is laminated. or
(ii) a first alloy layer; Insulating film; And a double-sided flexible metal laminate on which a second alloy layer is laminated. The method of claim 16,
The flexible metal composite substrate,
A first coverlay film; Double-sided flexible metal laminate; And a second coverlay film is laminated,
The first alloy layer is disposed between the first adhesive layer and the insulating film of the first coverlay film,
The second alloy layer is disposed between the second adhesive layer of the second coverlay film and the insulating film, and the flexible metal composite substrate in which they are integrated. The method of claim 16,
The flexible metal composite substrate,
A first coverlay film; Single-sided flexible metal laminate; Double-sided flexible metal laminate; And a second coverlay film is laminated,
The flexible metal composite substrate further comprising an adhesive layer disposed between the insulating film of the single-sided flexible metal laminate and the first alloy layer of the double-sided flexible metal laminate. The method of claim 15,
At least one of the alloy layers is a flexible metal composite substrate including one or more circuit patterns patterned in a predetermined shape. The method of claim 15,
The average operating temperature of the flexible metal composite substrate is 65 °C ± 10%, the maximum temperature is 120 °C or less, the flexible metal composite substrate. The method of claim 15,
Flexible metal composite substrate applied to optical modules for optical communication.

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