Method for producing flexible copper foil laminated film having PTFE substrate

Abstract

The present invention provides a method for manufacturing a flexible copper foil laminated film having a PTFE substrate, the method for manufacturing a flexible copper foil laminated film having a PTFE substrate according to an embodiment of the present invention comprising: a PTFE substrate preparation step of preparing a substrate comprising a PTFE material in a chamber space of a vacuum chamber; a reaction gas injection step in which a reaction gas is injected after the chamber space of the vacuum chamber is vacuumized for a sputtering process; a high-frequency power access step of accessing high-frequency power to a target which is installed at the upper part of the interior of the vacuum chamber and is composed of single-crystal metal particles; and a metal thin film lamination step of depositing the metal particles separated from the target on the upper part of the PTFE substrate under the action of the accessed high-frequency power and forming a metal thin film.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a flexible copper clad laminate film having a PTFE substrate. More specifically, the present invention relates to a method for manufacturing a flexible copper clad laminate film having a PTFE substrate, wherein a metal thin film is uniformly deposited on a PTFE substrate in order to manufacture a flexible copper clad laminate film (FCCL), thereby improving the electrical performance of the flexible copper clad laminate film and preventing the physical properties of the PTFE substrate from being reduced. Background Art

[0002] Flexible copper clad laminate (FCCL) is the core material of flexible printed circuit board (FPCB) mainly used in smart phones, PCs, semiconductors, vehicle electrical equipment, displays, mobility, secondary batteries, etc. Generally, flexible copper clad laminate FCCL is a product in which a metal film is laminated on both sides or one side of a polymer substrate.

[0003] The substrate constituting the flexible copper foil laminate film FCCL can be made of various insulating materials such as polyimide (PI) resin, thermoplastic resin, glass, epoxy resin, liquid crystal polymer (LCP), etc., but preferably, polytetrafluoroethylene (PTFE) material with excellent mechanical and electrical properties is used.

[0004] Polytetrafluoroethylene (hereinafter referred to as 'PTFE') material has excellent mechanical properties such as chemical resistance, heat resistance, dimensional stability, etc., and has a lower dielectric constant and dielectric loss than other insulating materials. When applied to a printed circuit board PCB, it has the advantage of faster signal and data transmission speed in the same antenna circuit. However, since the metal bonding strength of PTFE is poorer than that of other insulating materials, it is necessary to pay attention to the method for supplementing the bonding strength between the PTFE substrate and the metal.

[0005] Figure 1 Various methods for manufacturing the flexible copper foil laminate film FCCL in the prior art are shown.

[0006] In the manufacture of flexible copper foil laminated film FCCL, there are many manufacturing process methods for bonding substrate and copper film. Figure 1 The laminating process shown in part (a) is a method of coating an adhesive 30 on one or both sides of a PTFE substrate 10 to bond a copper thin film 20. Figure 1 The casting process shown in part (b) is a method of casting a solution of an insulating resin 40 mixed with polyimide (PI) and PTFE onto the copper thin film 20 and bonding a substrate composed of the insulating resin 40 to the copper thin film 20. Figure 1 The coating process shown in (c) is a method in which, after the PTFE substrate 10 is impregnated with polyimide (PI), a copper molten solution 50 is plated with gold or coated on the impregnated PTFE substrate 10 to bond the copper thin film 20 .

[0007] like Figure 1 As shown, in the manufacturing method of the flexible copper foil laminated film FCCL in the prior art, due to the use of an adhesive or polyimide (PI), the dielectric constant of the flexible copper foil laminated film FCCL increases compared to the case of using the PTFE substrate 10 alone, thereby causing a problem of slower signal and data transmission speeds.

[0008] Therefore, a sputtering process of directly depositing a copper thin film on the PTFE substrate 10 is suggested, which can prevent problems such as a decrease in the conveying speed of the flexible copper foil laminate film FCCL caused by using an adhesive or PI as in the prior art.

[0009] The sputtering process is a type of vacuum deposition method mainly used in the production of integrated circuits. It is a process in which ionized gas is accelerated under a relatively low vacuum and collides with a target, ejecting atoms and forming a thin film on a substrate. In such a sputtering process, it is particularly important to control the metal particles constituting the thin film to be uniformly deposited on the substrate in order to remove electrical noise and even physical vibrations.

[0010] In the related prior art, Korean Patent Publication No. 10-2022-0049366 discloses a sputtering device that controls particles coming out of a target in units of atomic layers so that a metal film is uniformly grown on a substrate.

[0011] In addition, when a sputtering device based on the above-mentioned prior art is used to form a metal film on a substrate using a variety of materials, a metal film is uniformly formed on a substrate having a crystalline structure such as sapphire (aluminum oxide), but it is not easy to control the atomic layer on a substrate made of PTFE material, so the metal film cannot be uniformly formed. During the deposition process, the PTFE substrate is physically damaged or deformed, resulting in a problem of reduced quality of the flexible copper foil laminate film FCCL.

[0012] Recently, with the development of cutting-edge industries such as communications, displays, semiconductors, and secondary batteries, the demand for flexible copper foil laminated films FCCL has increased sharply. However, there is currently almost no technology that can uniformly deposit a metal thin film on a PTFE substrate that is widely used as a substrate material for FCCL.

[0013] Therefore, in order to manufacture a flexible copper clad laminate (FCCL), it is urgently necessary to develop a method for manufacturing a flexible copper clad laminate having a PTFE substrate, which can uniformly deposit a metal film on the PTFE substrate while eliminating the use of a binder or a resin such as polyimide (PI) as in the prior art, thereby improving the electrical properties of the flexible copper clad laminate FCCL and preventing the physical properties of the PTFE substrate from being reduced. Summary of the invention

[0014] Technical issues

[0015] The object of the present invention is to provide a method for manufacturing a flexible copper clad laminate having a PTFE substrate, in order to manufacture a flexible copper clad laminate (FCCL), by uniformly depositing a metal film on the PTFE substrate, thereby improving the electrical properties of the flexible copper clad laminate FCCL and preventing the physical properties of the PTFE substrate from being reduced.

[0016] Technical Solution

[0017] In order to solve the technical problem, the manufacturing method of the flexible copper foil laminated film with a PTFE substrate of the present invention may include: a PTFE substrate preparation step, preparing a substrate made of PTFE (Polytetrafluoroethylene) material in the chamber space of a vacuum chamber; a reaction gas injection step, injecting reaction gas after evacuating the chamber space of the vacuum chamber for the sputtering process; a high-frequency power connection step, connecting high-frequency power to a target installed in the upper part of the interior of the vacuum chamber and composed of single-crystal metal particles; and a metal film stacking step, under the action of the connected high-frequency power, the metal particles separated from the target are deposited on the upper part of the PTFE substrate to form a metal film.

[0018] Furthermore, in the PTFE substrate preparation step, the chamber space temperature of the vacuum chamber in which the PTFE substrate is prepared may be set to a range of 140 degrees (° C.) to 200 degrees (° C.).

[0019] In addition, in the reaction gas injection step, the gas injected into the chamber space of the vacuum chamber may include argon (Ar).

[0020] In this case, in the high-frequency power supplying step, the high-frequency power may be transmitted to the target installed at the upper end of the interior of the vacuum chamber through a power supply line composed of a single crystal copper wire.

[0021] In this case, in the metal thin film lamination step, the metal thin film may be deposited on the upper portion of the PTFE substrate by an atomic sputtering epitaxy (ASE) process in which metal particles in atomic units are laminated on the upper portion of the PTFE.

[0022] Also, in the metal thin film lamination step, the metal thin film may be laminated on the upper portion of the PTFE substrate with a thickness ranging from 100 to 300 nm.

[0023] Furthermore, in the metal thin film lamination step, the metal particles may include copper (Cu).

[0024] Wherein, in the metal thin film lamination step, during the deposition of metal particles separated from the target onto the upper portion of the PTFE substrate, vibration transmitted to the vacuum chamber may be absorbed or blocked.

[0025] Furthermore, the method further comprises: a metal thin film pattern forming step of forming a pattern having a specific shape on the surface of the metal thin film laminated on the upper part of the PTFE substrate.

[0026] Furthermore, in the metal thin film pattern forming step, the formed pattern may be in a hexagonal honeycomb shape with a line width of 5 μm to 14 μm.

[0027] Technical Effects

[0028] According to the manufacturing method of the flexible copper foil laminated film with a PTFE substrate of the present invention, the bonding force between the PTFE substrate and the metal film is improved by using the atomic sputtering epitaxy (ASE) process, and the metal film is uniformly deposited on the PTFE substrate, thereby improving the electrical properties of the flexible copper foil laminated film and having excellent heat resistance and mechanical properties, so that it can be used as a high-tech material used in various industrial fields such as communications, semiconductors, displays, and secondary batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Various methods for producing the conventional flexible copper foil laminate film FCCL are shown.

[0030] Figure 2It is the initial growth mechanism of metal films deposited on sapphire substrates by atomic sputtering epitaxy (ASE) process.

[0031] Figure 3 1 is a flow chart of a method for producing a flexible copper foil laminate film having a PTFE substrate according to the present invention.

[0032] Figure 4 The images of each PTFE substrate before and after copper deposition were observed using a scanning electron microscope (SEM).

[0033] Figure 5 Electron beam scatter diffraction (EBSD) was used to observe the surface of copper deposited on PTFE.

[0034] Figure 6 The present invention is a photograph of a mesh and a circuit image of a copper thin film patterned on a PTFE substrate by the method for producing a flexible copper foil laminate film with a PTFE substrate according to the present invention.

[0035] Figure 7 An image showing the results of an x-ray diffraction experiment of a Cu / e-PTFE thin film produced by the method for producing a flexible copper foil laminated film having a PTFE substrate according to the present invention.

[0036] Figure 8 An AFM surface image of a Cu / e-PTFE thin film manufactured by the method for manufacturing a flexible copper foil laminated film having a PTFE substrate according to the present invention is shown.

[0037] Fig. 9 Another example of an AFM surface image of a Cu / e-PTFE thin film manufactured by the method for manufacturing a flexible copper foil laminated film having a PTFE substrate according to the present invention is shown.

[0038] Fig.10 Still another example of an AFM surface image of a Cu / e-PTFE thin film manufactured by the method for manufacturing a flexible copper foil laminated film having a PTFE substrate according to the present invention is shown.

[0039] Fig.11 The SEM image of the Cu / e-PTFE thin film manufactured by the method for manufacturing a flexible copper foil laminated film having a PTFE substrate according to the present invention is shown. DETAILED DESCRIPTION

[0040] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein, but may also be embodied in other forms. Instead, the embodiments introduced herein are provided to make the disclosed contents more thorough and complete, and to fully convey the ideas of the present invention to those skilled in the art. Throughout the specification, the same reference numerals represent the same constituent elements.

[0041] The method for manufacturing a flexible copper foil laminated film having a PTFE substrate according to the present invention is characterized in that an atomic sputtering epitaxy (ASE) process is used to improve the bonding strength between the PTFE substrate and the metal film and to uniformly deposit the metal film on the PTFE substrate. Figure 2 The atomic sputtering epitaxy (ASE) process used in the present invention is described.

[0042] Figure 2 It is the initial growth mechanism of the metal film 20 deposited on the sapphire (Al2O3) substrate 10s by an atomic sputtering epitaxy (ASE) process.

[0043] like Figure 2 As shown, the initial growth mechanism of the metal film 20 is generally composed of three steps from step (a) to step (c). Specifically, step (a) is a step in which the ejected metal particles 21 grow in the shape of nanodroplets, step (b) is a step in which the metal particles 21 in the shape of nanodroplets are integrated with each other, and step (c) is a step in which the metal particles 21 grow in multiple layers.

[0044] In a general sputtering process, a polycrystalline metal film 20 is deposited on a sapphire substrate 10s to form a grain boundary on the polycrystalline metal film 20. A grain boundary refers to a thin migration layer that constitutes a boundary between crystals. During the crystal growth process, the vicinity is finally solidified and includes impurities or combines with oxygen atoms to generate copper oxide. Therefore, in a general sputtering process, there is a problem that the copper film 20 cannot be grown epitaxially on the upper part of the sapphire substrate 10s.

[0045] In view of this, an atomic sputtering epitaxy (ASE) process is performed to realize an ultra-flat copper thin film 20 at a single atomic layer level on the upper portion of the sapphire substrate 10 s, thereby preventing copper from being oxidized.

[0046] In addition, in a general sputtering process, metal particles 21 are ejected from a target material as a whole and deposited on a coating surface, while the atomic sputtering epitaxy (ASE) process is a thin film growth method that stacks atoms one by one on a coating surface like code conversion. The atomic sputtering epitaxy (ASE) process is described in more detail below.

[0047] Generally speaking, copper (Cu) is the most widely used conductor in electrical civilization. However, oxidation, a fatal weakness, limits the use of copper, so that gold, a precious metal, is used in ultra-precision materials or circuits that need to ensure high reliability, even though its conductivity is poorer than that of copper but its price is much higher. Although various studies have been conducted on copper oxidation, only phenomenological states are described or theoretical predictions are reported. As the material becomes more miniaturized and highly integrated, it is more important to ensure sufficient service life and miniaturization of the power supply unit, so it is necessary to equip it with a material with high conductivity. In this context, the copper oxidation problem can be solved on a sapphire substrate 10s by performing an atomic sputtering epitaxy (ASE) process.

[0048] It is known from experience that copper starts to oxidize from the rough part, so the top priority is to produce a thin film with a good surface condition as much as possible. Therefore, an atomic sputtering epitaxy (ASE) process method can be used to grow a thin film with an ultra-flat surface at the atomic layer level on the sapphire substrate 10s.

[0049] The metal film 20 manufactured on the sapphire substrate 10s is in a single crystal state and has an ultra-flat surface with an RMS roughness of less than 0.2nm, and will not be oxidized even if exposed to the air for a long time. Through high-resolution electron microscope observation, if the surface is kept within a single atomic layer of roughness, phase migration caused by oxidation will not occur. According to the results of the oxygen permeability energy calculated according to the surface state by first principles calculation, when the surface is kept within a single atomic layer of roughness, in order for oxygen to penetrate into the metal film 20, energy needs to be supplied from the outside, so oxidation will not easily occur. In addition, in the absence of chemical bonding, if the oxygen occupancy rate of the physically adsorbed surface exceeds 50%, there is a self-regulating function that generates repulsion and suppresses oxidation by itself.

[0050] As mentioned above, by performing the atomic sputtering epitaxy (ASE) process, the oxidation of copper has a great impact on the material industry, and it can be applied to many fields where copper replaces the previous gold (Au). In particular, with the development of nanoscience, the line width of the circuit becomes smaller and the integration becomes higher. The oxidation of thinner conductive wires will cause more serious problems. On the contrary, there is no need to worry about oxidation problems for ultra-flat single crystal films, so its application range is very wide. From an economic point of view, it can bring an opportunity for copper films to completely replace gold used in nanocircuits. Since the conductivity of copper is about 40% better than that of gold, and if it is a single crystal copper film with an ultra-flat surface, the conductivity can be further increased by 15% or more compared to general copper, so its economic added value is very high in terms of power consumption and energy saving, extended use time, and miniaturization of equipment.

[0051] In addition, although a technology for depositing a metal film 20 such as a copper film on a sapphire (aluminum oxide, Al2O3) substrate 10s by performing the above-mentioned atomic sputtering epitaxy (ASE) process has been introduced, a technology for uniformly depositing a copper film on a PTFE substrate 10 by adopting the above-mentioned atomic sputtering epitaxy (ASE) process has not been introduced.

[0052] Polytetrafluoroethylene (PTFE) has excellent low dielectric properties while maintaining sufficient mechanical properties. In particular, when PTFE material is applied to the substrate of flexible copper cladlaminate (FCCL), it can reduce data loss and increase transmission speed. Therefore, it has become one of the materials that has received widespread attention recently.

[0053] However, when a copper film is deposited on the PTFE substrate 10 by performing an atomic sputtering epitaxy (ASE) process, unlike a crystalline substrate composed of aluminum oxide (Al2O3) and the like, since the PTFE material is a polymer material that is relatively fragile to environmental variables such as temperature and pressure, its physical properties are easily changed during the deposition process, resulting in process difficulties such as reduced quality of the FCCL.

[0054] Furthermore, when an atomic sputtering epitaxy (ASE) process is performed to deposit a copper film on the PTFE substrate 10, unlike a crystalline substrate such as a sapphire substrate 10s, due to insufficient adsorption energy between the PTFE substrate 10 and the copper film, the copper film is easily detached from the PTFE substrate 10 and the conductivity is reduced.

[0055] Therefore, the present invention adopts the atomic sputtering epitaxy (ASE) process introduced in the prior art and improves the deposition conditions in accordance with the substrate material, so that the uniform metal film 20 can be easily deposited on the PTFE substrate 10, so that the flexible copper foil laminate film FCCL has excellent electrical properties and can improve the adsorption at the interface between the PTFE substrate 10 and the metal film 20.

[0056] Figure 3 1 is a process flow chart of a method for manufacturing a flexible copper foil laminate film having a PTFE substrate according to the present invention.

[0057] like Figure 3 As shown, according to the present invention, the manufacturing method of the flexible copper foil laminated film with a PTFE substrate includes: a PTFE substrate preparation step S100, preparing a substrate made of PTFE (Polytetrafluoroethylene) material in the chamber space of a vacuum chamber; a reaction gas injection step S200, in order to perform a sputtering process, the chamber space of the vacuum chamber is formed into a vacuum and then the reaction gas is injected; a high-frequency power connection step S300, connecting high-frequency power to a target, the target is installed at the upper end of the interior of the vacuum chamber and is composed of single-crystal metal particles; and a metal film stacking step S400, under the action of the connected high-frequency power, the metal particles separated from the target are deposited on the upper part of the PTFE substrate 10, thereby stacking a metal film 20.

[0058] The present invention provides a method for manufacturing a PTFE-based flexible copper clad laminate substrate. When manufacturing a flexible copper clad laminate (FCCL), an atomic sputtering epitaxy (ASE) process is used to control the crystal structure of a metal film 20 in atomic layer units on a PTFE substrate 10 constituting the flexible copper clad laminate FCCL, thereby being able to control high-quality metal films 20.

[0059] Figure 3The sputtering device used in the method for manufacturing the PTFE-based flexible copper foil laminate substrate according to the present invention is a device for removing noise, electrical noise and mechanical noise of a target substance from a general sputtering device, and performs the aforementioned atomic sputtering epitaxy (ASE) process.

[0060] The method for manufacturing a PTFE-based flexible copper foil laminate substrate according to the present invention is performed by a sputtering device including a vacuum chamber, an RF generating part, a vacuum pump part, a gas supply part, and a vibration blocking part.

[0061] First, a PTFE substrate preparation step S100 is performed to prepare a substrate made of PTFE (Polytetrafluoroethylene) material in a chamber space of a vacuum chamber.

[0062] Among them, the vacuum chamber is a space for performing a sputtering process to deposit a metal film 20 on a PTFE substrate 10, and the vacuum chamber includes a PTFE substrate, a target, and a chamber space. The PTFE substrate 10 serves as the anode part of the sputtering process, and is composed of its polytetrafluoroethylene (PTFE) material. The target is located at the cathode part opposite to the PTFE substrate 10, and the target is formed by a metal substance of a thin film to be deposited on the PTFE substrate 10. The PTFE substrate 10 and the target as described above are located inside the chamber space, so that particles falling off from the target in the subsequent sputtering process are separated and deposited on the PTFE substrate 10, thereby manufacturing a metal film 20.

[0063] In the PTFE substrate preparation step S100, the chamber space temperature of the vacuum chamber for preparing the PTFE substrate 10 can be formed and maintained in the range of 140 degrees (°C) to 200 degrees (°C), preferably formed and maintained in the range of 150 degrees (°C) to 170 degrees (°C). When the temperature inside the chamber space is less than 140 degrees (°C), the metal film 20 deposited on the PTFE substrate 10 cannot be formed uniformly, and when the temperature inside the chamber space is greater than 200 degrees (°C), there is a problem that the physical properties of the PTFE substrate 10 change.

[0064] Furthermore, in the method for manufacturing a PTFE-based flexible copper foil laminate substrate according to the present invention, the pressure condition or vacuum condition inside the chamber space is optimized through repeated experiments so that the crystalline PTFE of the metal film 20 can grow uniformly on the substrate 10. Further, the PTFE substrate 10 is pretreated so that the metal film 20 can grow at the interface of the PTFE substrate 10 in a manner having high adsorption.

[0065] Next, the reaction gas injection step S200 and the high frequency power connection step S300 of the present invention may be performed in sequence.

[0066] The reaction gas injection step S200 is a step of injecting reaction gas after forming the chamber space of the vacuum chamber into a vacuum for the sputtering process, and the high-frequency power connection step S300 is a step of connecting high-frequency power to a target installed in the upper part of the interior of the vacuum chamber and composed of single crystal metal particles.

[0067] The reaction gas injection step S200 and the high frequency power connection step S300 are respectively performed by a gas supply unit and an RF generation unit constituting a sputtering device.

[0068] The RF generating unit for performing the high frequency power supply step S300 is configured to supply RF power as high frequency power to a target in a vacuum chamber for a sputtering process, and is connected to the target via a connecting wire.

[0069] In addition, in order to perform the sputtering process, the chamber space needs to be in a vacuum state. The vacuum pump part of the sputtering device is a structure that sucks the fluid inside the chamber space to form a vacuum inside the chamber space of the vacuum chamber. It is a commonly used rotary pump.

[0070] To this end, a gas supply unit for supplying a reaction gas for performing a sputtering process inside a chamber space in a vacuum state is connected to the chamber space of the vacuum chamber. The reaction gas supplied by the gas supply unit may be argon (Ar) gas. The higher the purity of the argon gas, the more the deposited particles are homogeneously separated from the target on the entire surface of the target and the metal thin film stacking step S400 is performed.

[0071] In the metal film stacking step S400, as a component of the aforementioned sputtering device, when RF power is connected to the target in the chamber space supplied with reaction gas under a vacuum state through the RF generating part, under the action of glow discharge, the reaction gas is ionized and plasma discharge is generated between the PTFE substrate 10 and the target. The cations existing in the discharge area hit the surface of the target due to the electrical power, so that the deposited particles falling from the target surface are deposited on the PTFE substrate 10 facing it, thereby manufacturing the metal film 20.

[0072] In addition, when executing the high-frequency power access step S300 of the present invention, the power cable that supplies power to the RF generating part is formed into a single crystal copper metal wire, thereby avoiding noise and signal distortion mixed into the signal transmitted to the power cable, and the stability of the RF power accessed to the target is improved, so that the deposited particles fall out uniformly from the entire surface of the target, thereby improving the quality of the metal film 20 deposited on the PTFE substrate 10.

[0073] Furthermore, when considering the separation of the deposited particles from the target, the homogeneity of the deposited particles falling from the target is associated with the crystallinity of the target. Therefore, the target included in the vacuum chamber can be formed as a single crystal metal. As described above, in the case where the target is formed as a single crystal metal, the metal particles will be uniformly formed with a constant directionality over the entire surface of the target, and the deposited particles separated therefrom will also be in a homogeneous state, thereby enabling the deposited metal film 20 to be manufactured with high quality. The type of single crystal metal forming the target is determined according to the type of metal film 20 to be deposited on the PTFE substrate 10, and it can be copper, silver, or a single element metal.

[0074] Furthermore, when the high frequency power connection step S300 is performed, the connection wire for transmitting the RF power of the RF generator to the target in the vacuum chamber can also be formed by a single crystal copper wire. Thus, the electrical noise can be removed from the RF power connected to the target and the power stability can be improved. Since the homogeneity of the plasma discharge formed between the PTFE substrate 10 and the target can be improved, the deposition particles can be uniformly dropped from the entire surface of the target.

[0075] The outdoor grounding portion formed for grounding the RF generating portion can be formed as a single crystal copper bulk. When the metal type of the target is copper, the single crystal copper constituting the outdoor grounding portion can be manufactured in the same manner as the target. As described above, when the outdoor grounding portion is formed as a single crystal copper bulk, the stability of the RF power can be improved, so that the deposited particles can be dropped uniformly.

[0076] In addition, in the metal film stacking step S400, the present invention prevents mechanical noise (e.g., vibration) from being applied to the PTFE substrate 10 during the deposition of the deposited particles dropped from the target, so that the metal film 20 grows in a highly adsorbable manner at the interface with the PTFE film.

[0077] To this end, the corners of the bottom surface of the vacuum chamber may be supported by a vibration barrier to prevent the vibration from being transmitted from the bottom surface. The vibration barrier has a mechanically non-reversible structure so that the vibration of the bottom surface is not transmitted to the vacuum chamber, but the vibration generated in the vacuum chamber is discharged to the outside (bottom surface) and offset.

[0078] Specifically, the vibration blocking part for blocking the vibration transmitted to the vacuum chamber in the metal film lamination step S400 includes a spike and a damping pad. The spike is attached to the bottom surface of the vacuum chamber and supports the vacuum chamber, and has an angle shape that becomes sharper toward the bottom surface. The damping pad is placed above the bottom surface and accommodates the spike thereon, and an insertion groove for accommodating the tip of the spike is formed on the damping pad. By accommodating the spike in the insertion groove of the damping pad, the planar position of the spike is fixed.

[0079] By using the vibration-blocking part including the spike and the damping pad as described above, the vibration generated by the bottom surface only shakes the damping pad, but cannot apply a force to the spike, so that the vibration is not transmitted to the vacuum chamber supported by the spike. As a result, the vacuum chamber is not affected by the vibration of the bottom surface, and in the process of the deposited particles separated from the target being deposited on the PTFE substrate 10, no physical external force is transmitted, and the particles are uniformly deposited on the PTFE substrate 10, thereby improving the quality of the metal film 20. In addition, the spike can be angular in shape, and can be formed into various shapes such as a cone, a triangular pyramid, and a quadrangular pyramid.

[0080] Furthermore, in order to further block physical vibrations transmitted to the vacuum chamber, the vacuum chamber and the vacuum pump unit may be physically separated in the sputtering device used for the method for producing the PTFE-based flexible copper foil laminate substrate of the present invention.

[0081] As an example of a vacuum pump unit, a rotary pump generates a lot of vibrations due to the action of the pump during the process of sucking in fluid to make the chamber space of the vacuum chamber reach a vacuum. When the vacuum chamber and the vacuum pump unit are physically constructed together, the vibrations generated during the operation of the vacuum pump unit will be directly transmitted to the vacuum chamber, so that the deposited particles deposited on the PTFE substrate 10 will not be formed uniformly.

[0082] Therefore, the vacuum pump part is physically separated from the vacuum chamber, and the connection with the chamber space is achieved by a rubber pump line, and in order to block the vibration of the pump line from being transmitted to the vacuum chamber, the center of the pump line can be fixed to the wall connected to the bottom surface.

[0083] In addition, when the vacuum pump part is physically separated from the vacuum chamber, the vacuum pump part itself as described above also needs to be isolated from vibration, and the corners of its bottom surface can be supported by a vibration barrier part so that the vacuum chamber can avoid vibration transmission from the bottom surface.

[0084] Figure 4 Part (a) is an image of a pure PTFE substrate without copper laminated thereon observed using a scanning electron microscope (SEM). Figure 4 Part (b) is an image of a PTFE substrate laminated with copper observed using a SEM.

[0085] In addition, if Figure 4 As shown in part (a) of FIG. 1 , although it is difficult to observe the PTFE surface using a scanning electron microscope (SEM) due to the charging effect of electrons, when the PTFE substrate 10 is magnified and observed at 500 times and 5000 times, it is confirmed that the surface is rough and uneven. Figure 4 As shown in part (b), when a copper thin film with a thickness of 200 nm is deposited on the PTFE substrate 10 using the aforementioned sputtering device and an atomic sputtering epitaxy (ASE) process, it can be confirmed that the deposition is performed very uniformly while maintaining the original shape of the PTFE.

[0086] Figure 5 Electron beam scatter diffraction (EBSD) was used to observe the surface of copper deposited on PTFE.

[0087] like Figure 5 As shown in part (a) of FIG. 1 , when observing a map using electron beam scatter diffraction (EBSD) of a copper surface deposited on PTFE with a thickness of 200 nm, it can be confirmed that all copper grains are arranged in directions different from each other.

[0088] Figure 5 Part (b) of Figure 5 Part (c) shows the surface points of the grain measured in different axial directions of the crystal, which represent the inverse pole figure (IPF) and the pole figure (PF). It can be confirmed that the directions of the crystals are dispersed from each other in very various directions.

[0089] Figure 5Part (d) shows an IQ image of a misorientation map showing the boundary lines between grains, which is displayed in a very blue color to the extent that the misorientation lines are almost invisible. Among them, red is a line that satisfies the twin boundary conditions, and blue represents a grain boundary in any direction that does not meet the specific conditions. The fact that there is almost no red and only blue indicates that the particles are dispersed in a very variety of directions.

[0090] When the general Figure 5 When the image shown in part (d) of FIG. 1 is enlarged, it can be seen that Figure 5 As shown in part (e) of FIG. 1 (scale bar: 100 nm), particles are observed and their sizes are uniform and densely arranged as a whole, and the maximum size of the particles is about 10 nm. Such a small particle size minimizes the atomic spacing in the grain boundary and minimizes the gap, so that even in a polycrystalline structure, the space for oxygen or external impurities to enter can be reduced, which brings about the effect of minimizing the progress of oxidation and preventing the formation of copper oxides.

[0091] According to the method for manufacturing a flexible copper foil laminated film with a PTFE substrate of the present invention, a metal film pattern forming step S500 may be further performed, wherein a pattern p having a specific shape is formed on the surface of the metal film 20 laminated on the PTFE substrate 10 .

[0092] Figure 6 The following are mesh and circuit image photographs of a copper thin film deposited on a PTFE substrate patterned by the method for manufacturing a flexible copper foil laminated film with a PTFE substrate according to the present invention.

[0093] Figure 6 Part (b) of Figure 6 Part (c) shows an enlarged image of a hexagonal honeycomb mesh patterned by a photoresist process on a copper thin film deposited on a PTFE substrate 10 using the method for manufacturing a flexible copper foil laminated film with a PTFE substrate according to the present invention, Figure 6 Part (b) of Figure 6 The images shown in part (c) were taken at magnifications of 40 and 250, respectively, using a transmission-type polarizing microscope.

[0094] Figure 6Part (d) shows an image of a circuit patterned by a photoresist process on a copper thin film deposited on a PTFE substrate 10 using the method for manufacturing a flexible copper foil laminated film having a PTFE substrate according to the present invention.

[0095] like Figure 6 As shown in part (a) of FIG. 1 , a hexagonal honeycomb mesh pattern p can be formed on a copper film deposited on an e-PTFE substrate. The mesh pattern p can be used to perform electrical connections using the copper film in products such as electronic devices or solar cells, and can improve durability by enhancing the surface of the copper film. The mesh pattern p can be achieved by drilling holes (holes) on the surface of the copper film at certain intervals and connecting copper wires inside.

[0096] The line width of the mesh pattern p formed by the metal film pattern forming step S500 is determined by the interval between the holes bored in the copper film. The smaller the line width, the lower the resistance. The open area of ​​the mesh pattern represents the area ratio occupied by the holes in the mesh pattern. The larger the open area, the easier the flow of current, so that electrical connection can be effectively performed.

[0097] The line width and open area of ​​such a mesh pattern p can be appropriately selected according to the electrical performance and production cost required in the flexible copper foil laminate film FCCL. Figure 6 In the example shown in part (a) of FIG. 1 , it was confirmed that the line width of the mesh pattern p of the copper thin film deposited on the e-PTFE substrate was about 10 μm and the open area was about 50 μm.

[0098] The mesh pattern of the copper film is a type of printed circuit board (PCB) used in electronic circuits, such as Figure 6 As shown in part (b) of FIG. 1 , in order to make electrical connections, a PTFE substrate 10 on which a copper film is deposited can be used to form a desired circuit pattern.

[0099] As described above, according to the method for manufacturing a flexible copper foil laminated film with a PTFE substrate of the present invention, when performing the sputtering process, by adjusting environmental variables (for example, process variables such as temperature, pressure, and vacuum degree inside the chamber space), refining the deposition conditions most suitable for the PTFE substrate 10, and performing a pretreatment process of the PTFE substrate 10, it is confirmed that even in the case of a PTFE substrate 10 instead of a conventional crystalline substrate, the metal film 20 can be uniformly deposited by performing an atomic sputtering epitaxy (ASE) process.

[0100] Specifically, as a result of performing an atomic sputtering epitaxy (ASE) process using the method for manufacturing a flexible copper foil laminated film with a PTFE substrate according to the present invention, it was confirmed that the crystal growth rate of the copper thin film was above about 10 nm / min, the grain size was at the level of 10 nm to 15 nm, and it was very uniform. The vacancy or staking defects caused by the grain boundary were minimized, and the surface roughness was at the level of about 0.5 nm.

[0101] Figure 7 An image showing an x-ray diffraction experiment result of a Cu / e-PTFE thin film having 300 nm of Cu deposited thereon by the method for manufacturing a flexible copper foil laminated film having a PTFE substrate according to the present invention.

[0102] like Figure 7 As shown in the x-ray diffraction experiment results of the Cu / e-PTFE film, there are multiple diffraction peaks of e-PTFE and diffraction peaks of copper on the image. In addition, it can be confirmed that there are diffraction peaks in multiple directions on the image, and it can be confirmed that both substances (e-PTFE and Cu) exist in a polycrystalline state. In addition, it is confirmed that although there are still particles (grains) corresponding to the (100) and (110) orientations, the orientation of Cu (111) direction is the most well developed.

[0103] Figure 8 The AFM surface image of the Cu / e-PTFE thin film manufactured by the method for manufacturing a flexible copper foil laminated film with a PTFE substrate according to the present invention is shown. Figure 8 In the AFM surface image of the Cu / e-PTFE film shown, it was confirmed that the RMS roughness was about 90.4 nm.

[0104] Fig. 9 Another example of an AFM surface image of a Cu / e-PTFE thin film manufactured using the method for manufacturing a flexible copper foil laminated film having a PTFE substrate according to the present invention is shown.

[0105] Specifically, Fig. 9 The AFM surface image of the Cu / e-PTFE film shown is Figure 8 The measuring range is reduced to 10 μm 2 (10μm×10μm) and the results of the measurement. Fig. 9The results of measurement in the AFM surface image of the Cu / e-PTFE film shown above confirmed that the RMS roughness was reduced to about 29.2 nm except for the defective portions of the e-PTFE.

[0106] Fig.10 Still another example of an AFM surface image of a Cu / e-PTFE thin film manufactured by the method for manufacturing a flexible copper foil laminated film having a PTFE substrate according to the present invention is shown.

[0107] Specifically, Fig.10 The AFM surface image of the Cu / e-PTFE film shown is Figure 8 The measuring range is reduced to 1 μm 2 (1μm×1μm) and measured the result. Fig.10 In the AFM surface image of the Cu / e-PTFE film shown, it was confirmed that most of the defects of the e-PTFE were removed, so that the RMS roughness was reduced to about 5 nm. In addition, it was confirmed that the copper (Cu) particles in the copper film deposited on the e-PTFE substrate existed in the form of fine particles.

[0108] Fig.11 SEM images of a Cu / e-PTFE thin film with 300 nm of Cu deposited thereon at various magnifications are shown by the method for manufacturing a flexible copper foil laminated film with a PTFE substrate according to the present invention.

[0109] The state of the e-PTFE substrate can be confirmed in the SEM image of the Cu / e-PTFE film at low magnification, and the shape of the deposited copper can be observed in the SEM image of the Cu / e-PTFE film at high magnification, which can be compared with the Fig.10 The copper (Cu) particles were confirmed to exist in the form of particles similarly to the results observed in .

[0110] According to the manufacturing method of the flexible copper foil laminated film with a PTFE substrate of the present invention, when the PTFE substrate 10 on which the metal film 20 is deposited by the atomic sputtering epitaxy (ASE) process is used in a semiconductor PCB, excellent high temperature resistance and oxidation resistance can be achieved. Therefore, it has the effect of being able to solve the problem of circuit performance degradation caused by server heating in ICT in the semiconductor industry.

[0111] Moreover, according to the manufacturing method of the flexible copper foil laminated film with a PTFE substrate of the present invention, the atomic sputtering epitaxy (ASE) process can be used to uniformly control the copper oxide layer on the PTFE substrate 10. The previous manufacturing method is to form a polycrystalline metal film 20 on the substrate, so that oxygen atoms are adsorbed on the grain boundaries inside the metal film 20, so that the oxidation process is irregular. On the other hand, the metal film 20 deposited on the PTFE substrate 10 according to the manufacturing method of the flexible copper foil laminated film using the PTFE substrate 10 of the present invention is a flat and dense film, so that the oxidation is carried out uniformly on the surface, so that the material that can ensure the reliability of 5G communication quality can be realized. In the previous communication industry, the copper oxide layer is formed due to the moisture content in the atmosphere (rain, resonance absorption of oxygen or water molecules in the air), so that there are problems of reduced communication quality and attenuation, and according to the manufacturing method of the flexible copper foil laminated film with a PTFE substrate of the present invention, because it can control the copper oxide layer in the copper film on the PTFE substrate 10, it can ensure the reliability of communication quality in a high-frequency environment.

[0112] Furthermore, according to the method for manufacturing a flexible copper foil laminated film with a PTFE substrate of the present invention, when a graphene film is grown using an atomic sputtering epitaxy (ASE) process in a copper thin film deposited on a PTFE substrate, the copper thin film will have extremely high thermal conductivity, and can be used as a heat dissipation material for various electronic components such as OLEDs.

[0113] Although this specification is described with reference to the preferred embodiments of the present invention, those skilled in the art may implement various modifications and variations to the present invention without departing from the scope of the concept and field of the present invention as described in the attached claims. Therefore, if the implementation of the variation substantially includes the constituent elements of the attached claims of the present invention, it should be considered to fall within the technical scope of the present invention.

Claims

1. A method for producing a flexible copper foil laminate film having a PTFE substrate, characterized in that: include: a PTFE substrate preparation step, preparing a substrate made of PTFE material in a chamber space of a vacuum chamber; A reaction gas injection step, in order to perform a sputtering process, the chamber space of the vacuum chamber is evacuated and then the reaction gas is injected; a high-frequency power supply step of supplying high-frequency power to a target composed of single-crystal metal particles installed at an upper portion of the interior of the vacuum chamber; and In the metal film lamination step, under the action of the high frequency power input, the metal particles separated from the target are deposited on the upper part of the PTFE substrate to form a metal film.

2. The method for producing a flexible copper foil laminated film having a PTFE substrate according to claim 1, characterized in that: In the PTFE substrate preparation step, the chamber space temperature of the vacuum chamber in which the PTFE substrate is prepared is in the range of 140° C. to 200° C.

3. The method for producing a flexible copper foil laminated film having a PTFE substrate according to claim 1, characterized in that: In the reaction gas injection step, the gas injected into the chamber space of the vacuum chamber includes argon (Ar).

4. The method for producing a flexible copper foil laminated film having a PTFE substrate according to claim 1, characterized in that: In the high-frequency power supplying step, the high-frequency power is transmitted to the target installed at the upper end of the interior of the vacuum chamber through a power supply line composed of a single-crystal copper wire.

5. The method for producing a flexible copper foil laminated film having a PTFE substrate according to claim 1, characterized in that: In the metal thin film lamination step, the metal thin film is deposited on the upper part of the PTFE substrate by an atomic sputtering epitaxy process in which metal particles in atomic units are laminated on the upper part of the PTFE.

6. The method for producing a flexible copper foil laminated film having a PTFE substrate according to claim 1, characterized in that: In the metal thin film lamination step, the metal thin film is laminated on the upper portion of the PTFE substrate with a thickness ranging from 100 nm to 300 nm.

7. The method for producing a flexible copper foil laminated film having a PTFE substrate according to claim 1, characterized in that: In the metal thin film lamination step, the metal particles include copper (Cu).

8. The method for producing a flexible copper foil laminated film having a PTFE substrate according to claim 1, characterized in that: In the metal thin film lamination step, during the deposition of metal particles separated from the target onto the upper portion of the PTFE substrate, vibration transmitted to the vacuum chamber is absorbed or blocked.

9. The method for producing a flexible copper foil laminated film having a PTFE substrate according to claim 1, characterized in that: Also includes: The metal thin film pattern forming step forms a pattern having a specific shape on the surface of the metal thin film that has been laminated on the upper part of the PTFE substrate.

10. The method for producing a flexible copper foil laminated film having a PTFE substrate according to claim 9, characterized in that: In the metal film pattern forming step, the formed pattern is in a hexagonal honeycomb shape with a line width of 5 μm to 14 μm.

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