High-Dielectric Multilayer PCB Substrate, Method for Manufacturing the Same, and RF Performance-Enhanced Cosmetic Treatment Device

Abstract

The present invention relates to a process for laminating and manufacturing a multilayer printed circuit board (PCB) using a ceramic / PTFE composite material having an average dielectric constant of 10.2 ± 0.3 and a loss factor of 0.0025 or less, and to the resulting product, thereby providing a circuit board specialized for RF (radio frequency) skin aesthetic medical devices. It presents a substrate structure and manufacturing technology capable of stably and efficiently delivering high-frequency energy to skin tissue.

Description

Technology Field

[0001] The present invention relates to a process for laminating and manufacturing a multilayer printed circuit board (PCB) and the resulting product, and provides a circuit board specialized for RF (radio frequency) medical devices for skin aesthetics. In particular, the present invention presents a substrate structure and manufacturing technology capable of stably and efficiently delivering high-frequency energy to skin tissue by simultaneously improving loss and impedance matching. Background Technology

[0002] Conventional RF medical devices for skin aesthetics have been manufactured based on FR-4 or low dielectric constant PTFE substrates. However, in the high frequency (1 MHz to 10 GHz) band, insertion loss and signal distortion increase, and the distribution of electromagnetic waves near the electrode (energy radiating part) is uneven, causing hot spots to occur. Furthermore, there were limitations in miniaturization and high integration through multilayering. Therefore, there is a need for a technology that can shorten the electrical length relative to the same area and simultaneously secure a uniform electric field distribution by applying a high dielectric constant insulating layer in a multilayer stacked structure.

[0003] Meanwhile, existing RF medical devices have faced difficulties in ensuring efficiency and safety due to significant RF energy loss and limitations in device size and thermal management. Consequently, issues such as non-uniformity in treatment efficacy, increased treatment time, and the potential for skin damage have been continuously raised. To address these problems, the introduction of high-dielectric constant PCB technology utilizing ceramic / PTFE composite materials is urgently needed. Prior art literature

[0004] Korean Published Patent Application No. 10-2017-0044840 (Date of publication: April 26, 2017) The problem to be solved

[0005] The present invention aims to solve the aforementioned problems, and the purpose of the present invention is to maximize the miniaturization and performance efficiency of the device by utilizing high dielectric constant ceramic / PTFE materials to dramatically improve the performance of RF medical devices suitable for the field of skin care.

[0006] In addition, the objective of the present invention is to provide a method for manufacturing a multilayer printed circuit board based on a high dielectric constant insulating layer stacking structure in which a high dielectric constant insulating layer is stably inserted and bonded to a multilayer stacking structure.

[0007] The technical problems to be solved by the present invention are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which the present invention belongs from the description below. means of solving the problem

[0008] A method for manufacturing a multilayer printed circuit board based on a high dielectric constant insulating layer stacking according to the present invention for achieving the above objective is a method for manufacturing a multilayer printed circuit board comprising an insulating layer formed by mixing a high dielectric constant ceramic and PTFE.

[0009] (a) a step of preparing a ceramic / PTFE composite material having an average dielectric constant of 10.2 ± 0.3 and a loss factor of 0.0025 or less; (b) a step of forming a dielectric layer by stacking the composite material; (c) a step of forming a copper conductive layer on one or both sides of the dielectric layer; (d) a step of alternately stacking a plurality of dielectric layers and conductive layers and forming vias to form interlayer electrical connections; and (e) a step of compressing and fixing the laminate through a lamination process, wherein the substrate minimizes losses in the high frequency (RF) band and enhances thermal conductivity and dimensional stability.

[0010] A multilayer printed circuit board based on a high dielectric constant insulating layer stacking according to another aspect of the present invention has a structure in which a non-pattern layer, a plurality of via coating layers, and drill hole layers are sequentially stacked, and

[0011] Each of the plurality of via coating layers comprises a dielectric layer in which ceramic and PTFE are mixed and the average dielectric constant is set within a predetermined range, a via plating layer formed on the inner wall of a via hole penetrating the dielectric layer, and copper conductive layers formed respectively on the front and back surfaces of the dielectric layer to be electrically connected to the via plating layer.

[0012] The plurality of via coating layers are arranged so that the copper conductive layers of each via coating layer come into contact with each other in a contact-to-contact state when stacked, and an insulating stacking layer is formed in the surrounding area of ​​the copper conductive layers arranged in a contact-to-contact state, and the insulating stacking layer supports the outer edge of the copper conductive layers, thereby maintaining interlayer electrical connection reliability between the via coating layers and simultaneously improving the mechanical stability of the stacked structure of the entire substrate.

[0013] In addition, according to the present invention, the insulating laminate is characterized by impregnating PP glass wool with resin in a range of more than 40% and less than or equal to 60% to prevent poor contact between the copper conductive layers placed face-to-face and to suppress bubble generation and lamination defects during lamination.

[0014] A medical device for improving high-frequency characteristics according to another aspect of the present invention comprises a printed circuit board manufactured according to a method of manufacturing a multilayer printed circuit board including an insulating layer formed by mixing a high-dielectric constant ceramic and PTFE, and is a medical device for improving high-frequency characteristics that performs cosmetic treatment by transmitting a high-frequency (RF) signal to the skin, comprising an RF electrode part, an RF oscillation and matching circuit part, a control processor, and a temperature sensor part, wherein the circuit board is manufactured based on a high-dielectric constant ceramic / PTFE composite material to reduce RF loss and ensure treatment accuracy and temperature stability. Effects of the invention

[0015] Through the above-mentioned means of solution, the present invention provides the following effects.

[0016] First, by applying a ceramic / PTFE composite material with an average dielectric constant of 10.2 ± 0.3 and a loss factor of 0.0025 or less, the same electrical length requirements can be achieved with a smaller physical area. The ceramic and PTFE composite material is compatible with existing PTFE processing processes, allowing it to be applied to existing production lines without equipment modification. Due to its low thermal expansion and dimensional stability, it improves the yield of multilayer lamination processes and reduces manufacturing defect rates. Furthermore, it enables stable operation in high-power RF environments without complex heat dissipation designs, thereby reducing design and production costs.

[0017] Second, the size and number of passive components (capacitors, inductors, etc.) can be reduced, thereby decreasing the overall circuit integration space and consequently significantly reducing the size and weight of RF medical devices. Stable impedance control is possible even in high-frequency environments, allowing multiple functional circuits (power supply, control unit, RF unit, etc.) to be integrated onto a single board. Interference between circuits is reduced, and signal integrity is maintained, enabling the realization of high-reliability therapeutic devices. While the overall performance of the device is improved, the potential for expansion into complex or smart medical devices is secured.

[0018] Third, this improves portability and ease of use, thereby increasing user satisfaction. Furthermore, it ensures excellent RF performance and treatment precision, while minimizing treatment safety and skin damage.

[0019] The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the configuration of the invention described in the detailed description or claims of the present invention. Brief explanation of the drawing

[0020] FIG. 1 illustrates a cross-sectional structure of a multilayer printed circuit board based on a high dielectric constant insulating layer stacking in one embodiment of the present invention. FIG. 2 is a perspective view illustrating the physical arrangement and components of each stacking process unit in which the PCB board of FIG. 1 is formed. Specific details for implementing the invention

[0021] Hereinafter, embodiments of the present invention are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. The present invention may be embodied in various different forms and is not limited to the embodiments described herein. In the drawings, parts unrelated to the explanation have been omitted to clearly explain the present invention, and the same reference numerals have been used for identical or similar components throughout the specification.

[0022] The words and terms used in this specification and claims are not limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention in accordance with the principles by which the inventor defines terms and concepts to best describe his invention.

[0023] Therefore, the embodiments described in this specification and the configurations illustrated in the drawings correspond to preferred embodiments of the present invention and do not represent all technical concepts of the present invention; thus, various equivalents and modifications that may replace such configurations may exist at the time of filing the present invention.

[0024] In this specification, terms such as “comprising” or “having” are intended to describe the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should not be understood as precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0025] The statement that a component is "in front," "rear," "upper," or "lower" of another component includes, unless there are special circumstances, not only being positioned "in front," "rear," "upper," or "lower" in direct contact with the other component, but also cases where another component is positioned in between. Furthermore, the statement that a component is "connected" to another component includes, unless there are special circumstances, not only being directly connected to each other, but also being indirectly connected to each other.

[0026] In this specification, singular expressions include plural expressions unless the context clearly specifies them as singular. Additionally, plural expressions include singular expressions unless the context clearly specifies them as plural. Throughout the specification, when a part is described as including a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0027] Hereinafter, preferred embodiments of the present invention will be described in detail in conjunction with the attached drawings.

[0028] FIG. 1 illustrates the cross-sectional structure of a multilayer printed circuit board (100) based on a high dielectric constant insulating layer stacking in one embodiment of the present invention.

[0029] Referring to FIG. 1, the substrate (100) includes a non-pattern layer (110) disposed on the top layer, a plurality of via coating layers (120) below it, and a drill hole layer (130) formed on the bottom layer.

[0030] Each via coating layer (120) includes a dielectric layer (121) mixed with high dielectric constant ceramic and PTFE, and the dielectric layer (121) is formed with a thickness of, for example, 40 mil (1000 μm) and provides high dielectric constant characteristics of εr ≈ 10.2 and a low loss factor (Df ≤ 0.0025). An upper copper conductive layer (123) and a lower copper conductive layer (124) are formed on both sides of the dielectric layer (121). Additionally, via holes are formed in the dielectric layer (121) through laser or mechanical drilling, and a via plating layer (122) is formed on the inner wall of the via hole with a thickness of, for example, 50 μm to provide an electrical conduction path.

[0031] As an important feature of the present invention, when a plurality of via coating layers (120) are stacked, the copper conductive layers (123, 124) of each via coating layer are arranged to come into direct contact with each other face-to-face, thereby forming a continuous and discontinuous electrical path between the layers and significantly reducing high-frequency signal transmission loss. This contact-to-contact structure plays a key role in minimizing impedance fluctuations and maximizing inter-layer connection reliability by excluding unnecessary insulating material intervention between the conductive layers.

[0032] Each via insulating layer (125, 126) is composed of prepreg material in which resin is impregnated into PP glass wool at a ratio of more than 40% and less than or equal to 60%. If the resin content is low at 40% or less, interlayer delamination or lamination defects may occur due to the generation of bubbles during the lamination process, and conversely, if the resin content is high at 60% or more, physical contact of the face-to-face copper conductive layer may be hindered due to excessive resin flow; therefore, in the present invention, the above range is set as the optimal critical condition.

[0033] In addition, the insulating laminate (125, 126) is designed to be formed only in the peripheral region of the face-to-face contact copper conductive layer as shown in FIG. 1, thereby allowing the copper conductive layers to directly contact each other's faces while supporting the outer region of the conductive layer to improve the mechanical strength and durability of the laminate structure. This allows the contact-to-contact structure between the conductive layers to be preserved by not having the insulating laminate entirely between the conductive layers, while effectively suppressing the risk of conductor deformation or delamination that may occur during the lamination pressure and heat treatment process.

[0034] A drill hole layer (130) having a plurality of drill holes (132) formed at the bottom of the substrate (100) is arranged to be electrically connected to the upper via coating layers (120) and performs an interface function for external connection of the entire circuit board.

[0035] As such, the structure of FIG. 1 repeatedly stacks high-dielectric constant dielectric layers and forms a continuous conduction path in the vertical direction through via plating layers of each layer. In addition, a structure is applied in which copper conductive layers are brought into contact with each other in a contact-to-contact manner to minimize signal loss in the high-frequency band. Furthermore, the insulating laminate is positioned to support the outer edge of the copper conductive layer while maintaining the resin impregnation rate within an optimal range, thereby suppressing lamination defects and increasing mechanical stability. With this configuration, the substrate (100) can simultaneously secure excellent signal transmission performance and stable thermal and mechanical properties even in a high-frequency environment.

[0036] FIG. 2 is a perspective view illustrating the physical arrangement and components of each stacking process unit in which the PCB substrate of FIG. 1 is formed.

[0037] Referring to FIG. 1, a multilayer printed circuit board according to the present invention has a plurality of high dielectric constant dielectric layers and conductive layers alternately stacked between prepreg insulating layers, and each conductive layer is electrically connected through via holes. A multilayer printed circuit board according to one embodiment of the present invention has the following stacking structure:

[0038] Based on the total thickness, each insulating layer is approximately 40 mil (1000 µm),

[0039] Each conductor layer (copper layer) is 50 µm,

[0040] The prepreg (PP) insulating layer has a thickness of 50 µm or 100 µm.

[0041] It follows a structure in which a double copper conductive layer is inserted in the center and symmetrically stacked on both sides.

[0042] This structure is designed to effectively accommodate multilayer signal transmission layers, ground layers, power layers, etc., and is configured so that the total interlayer thickness and conductor pattern thickness are matched to suit high-frequency characteristics.

[0043] Referring to FIG. 2, the multilayer printed circuit board based on a high dielectric constant insulating layer stacking of the present invention has a drill hole layer at the bottom, a plurality of via coating layers in the middle, and a non-pattern layer at the top, and the entire structure is composed of a stack.

[0044] The multilayer printed circuit board (PBC) is the overall stacked structure of the present invention.

[0045] The high dielectric constant layer is the RF-10-0400-CL1 insulating layer (40 mil thickness)

[0046] The conductive layer (copper foil) is a copper circuit layer 1 oz (35 μm) or 50 μm thick.

[0047] The prepreg insulating layer is an adhesive insulating layer with a thickness of 50 µm or 100 µm.

[0048] A via is a plated via hole for interlayer electrical connection.

[0049] The drill hole layer is the bottom drilled circuit board

[0050] The via coating layer is a layer containing vias and circuits located in the intermediate layer.

[0051] The non-patterned layer is the upper insulating layer without a pattern.

[0052] A stacked PCB unit is a structure in which conductive layers and dielectric layers are repeatedly stacked.

[0053] Materials and properties (see Fig. 2)

[0054] The PCB structure is based on the following high dielectric constant materials:

[0055] 1) Dielectric material: RF-10-0400-CL1 / CL1

[0056] Permittivity (ε) = 10.2

[0057] Dielectric thickness = 40 mil (approx. 1.0 mm)

[0058] Conductor layer: 1 oz / 1 oz copper double-sided

[0059] 2) Via-hole coating thickness: approx. 0.02 mm

[0060] Application of via coating via plating or conductive paste after laser processing or mechanical drilling

[0061] 3) Number of layers: Total 7 layers

[0062] Drill-Hole Layer (Drill-Hole PCB): Lower 1 layer

[0063] Via-Coating Layer (Via-Coating PCB): 5 Intermediate Layers

[0064] Non-Pattern Layer (Non-Pattern PCB): Top 1 layer

[0065] The manufacturing process for a multilayer PCB based on stacking high dielectric constant insulating layers is as follows.

[0066] 1. Cutting and Preparation of High Dielectric Sheets

[0067] The dielectric sheet is cut into 40 mil thick slices and prepared layer by layer.

[0068] 2. Formation of copper circuit pattern

[0069] After attaching 1 oz of copper to the top and bottom, signal lines, power layers, ground layers, etc. are formed by photolithography and etching.

[0070] 3. Via Hole Formation and Plating

[0071] The intermediate layer consists of a via-coating PCB, forms micro-vias for electrical connections, and establishes internal connections through plating (electrolytic or electroless) after laser or drilling.

[0072] 4. Lamination and Hot Pressing

[0073] Each prepared PCB unit layer is sequentially laminated, and compression lamination is performed under high temperature and high pressure conditions (e.g., 180 ℃, 2 MPa).

[0074] 5. Final Inspection and Surface Treatment

[0075] After evaluating insertion loss, reflection loss, and impedance characteristics, apply surface treatments such as ENIG or OSP if necessary.

[0076] The present invention can reduce device size and improve precision by utilizing high dielectric constant ceramic / PTFE materials. To this end, It is fabricated based on a PCB using a ceramic / PTFE composite material with a high dielectric constant (Dk). Compared to general PCB materials, it possesses a higher dielectric constant (approx. 10.2 ± 0.3), significantly reducing the board area for the same performance. Due to the high dielectric constant, the signal wavelength is shortened, allowing for a reduction in the size and number of passive components (e.g., capacitors, inductors, resonators) required within the circuit. The reduction in overall circuit size significantly lowers the weight and volume of the medical device, maximizing user portability and the precision of skin aesthetic treatments.

[0077] Ceramic / PTFE materials have a very low coefficient of thermal expansion (16 ppm / °C on the X-axis, 20 ppm / °C on the Y-axis, and 25 ppm / °C on the Z-axis), resulting in excellent thermal stability. These characteristics minimize shape changes and dimensional deformation of medical devices due to temperature changes, thereby maintaining continuous and consistent treatment precision.

[0078] Ceramic / PTFE composite materials exhibit excellent dimensional stability due to thin glass fiber reinforcement and maintain their shape even under thermal or mechanical stress during processing. This ensures stable production quality in medical device manufacturing processes that require repetitive and precise machining.

[0079] High-dielectric materials can efficiently implement the impedance control and high-frequency characteristics required at high frequencies within a small area. As a result, more functional and control circuits can be integrated into a limited space, enabling diversification of device functions and improvement of performance.

[0080] The miniaturization and precision of the device allow users to operate it more easily, enabling precise treatment, especially on sensitive and delicate skin areas such as the face. This enhances user convenience and significantly reduces the risk of side effects or misoperation, thereby improving treatment satisfaction and effectiveness.

[0081] The high dielectric constant ceramic / PTFE material used in the present invention exhibits a very low loss factor (Df=0.0025 @10 GHz), thereby minimizing RF signal loss. The low loss characteristics allow the applied RF energy to be accurately delivered to the skin and significantly reduce energy wasted during the treatment process.

[0082] It maximizes the effectiveness of the treatment by delivering concentrated energy to desired depths and areas within the skin without compromising RF signal quality. Stable and uniform RF energy guarantees consistent results in cosmetic treatments, such as improved skin elasticity, wrinkle reduction, and skin regeneration.

[0083] Reducing RF losses lowers the power required to achieve the same therapeutic effect, thereby shortening the overall treatment time. As treatment time is reduced, user convenience increases, and the equipment's operating lifespan and efficiency are improved, leading to reduced long-term operating costs.

[0084] It minimizes the conversion of lost RF energy into heat, thereby preventing overheating of the skin surface and internal tissues. By limiting the temperature rise, it reduces the risk of thermal damage to skin tissues and achieves high treatment efficiency while maintaining safe treatment conditions.

[0085] The material's low RF loss enables precise adjustment and maintenance of treatment parameters (frequency, output), thereby enhancing the predictability and reproducibility of treatment. This allows medical professionals and users to design treatment plans more accurately and maintain consistent therapeutic effects.

[0086] A skin aesthetic RF medical device to which the circuit board of the present invention is applied may be configured such that an RF electrode is exposed externally, and internally includes an RF matching circuit, a temperature sensor, and a control circuit. The RF electrode is a high-frequency electrode pattern placed on a skin contact surface, the RF matching circuit is a passive circuit (LC) for impedance matching connected to the electrode, the temperature sensor is a sensor element that detects temperature upon skin contact, and the control circuit (MCU) is a microcontroller circuit for RF output and temperature control. Miniaturization is possible by integrating a complex circuit, such as the skin contact electrode surface, RF matching network, temperature sensor, and microcontroller, onto a single multilayer substrate.

[0087] Although embodiments of the present invention have been described, the spirit of the present invention is not limited by the embodiments presented in this specification. Those skilled in the art who understand the spirit of the present invention may easily propose other embodiments within the scope of the same spirit by adding, changing, deleting, or adding components, and such are also to be considered to be included within the spirit of the present invention.

Claims

Claim 1 A method for manufacturing a multilayer printed circuit board comprising an insulating layer formed by mixing a high dielectric constant ceramic and PTFE, comprising: (a) a step of preparing a ceramic / PTFE composite material having an average dielectric constant of 10.2 ± 0.3 and a loss factor of 0.0025 or less; (b) a step of forming a dielectric layer by stacking the composite material; (c) a step of forming a copper conductive layer on one or both sides of the dielectric layer; (d) a step of forming a multilayer structure by alternately stacking a plurality of the dielectric layers and the conductive layer, forming a via hole penetrating the multilayer structure, and then forming a metal plating layer on the inner wall of the via hole to form an interlayer electrical connection; (e) a step of fixing the multilayer structure in which the dielectric layer and the copper conductive layer are stacked by laminating under predetermined temperature and pressure conditions to form an integrated multilayer structure, wherein the multilayer printed circuit board has a high dielectric constant ceramic / PTFE dielectric layer and a copper conductive layer alternately stacked, and the copper conductive layer is arranged in a face-to-face contact structure, thereby minimizing loss in the high frequency (RF) band, and A method for manufacturing a multilayer printed circuit board based on a stacked high dielectric constant insulating layer, characterized by being configured to improve thermal conductivity and dimensional stability. Claim 2 A method for manufacturing a multilayer printed circuit board based on a high dielectric constant insulating layer stack according to claim 1, wherein the dielectric layer is formed to a thickness of 1 mm. Claim 3 A multilayer printed circuit board comprising an insulating layer formed by mixing a high dielectric constant ceramic and PTFE, wherein the multilayer printed circuit board comprises: a non-pattern layer disposed at the top; and a plurality of via coating layers laminated below the above; A multilayer printed circuit board based on stacking high dielectric constant insulating layers, wherein the drill hole layers disposed at the bottom are sequentially stacked, and each of the plurality of via coating layers comprises: a dielectric layer in which an average dielectric constant is set to a predetermined range by mixing high dielectric constant ceramic and PTFE; a via plating layer continuously formed on the inner wall of a via hole formed to penetrate the dielectric layer; and a copper conductive layer formed on the front and back surfaces of the dielectric layer, respectively, so as to be electrically connected to the via plating layer, wherein when the plurality of via coating layers are stacked, the copper conductive layers of two via coating layers disposed adjacent to each other are arranged to be in direct face-to-face contact with each other, and an insulating stacking layer is formed in the peripheral region of the copper conductive layer in direct face-to-face contact, and the insulating stacking layer supports the outer portion of the copper conductive layer in direct face-to-face contact, thereby maintaining electrical connection reliability between the plurality of via coating layers and simultaneously improving the mechanical stability of the stacking structure of the multilayer printed circuit board. Claim 4 A multilayer printed circuit board based on a high dielectric constant insulating layer laminate according to claim 3, wherein the insulating laminate is formed from a prepreg in which resin is impregnated into PP glass wool in a range of more than 40% and less than or equal to 60%, thereby preventing poor contact between copper conductive layers directly disposed face-to-face and suppressing bubble generation and lamination defects during lamination. Claim 5 A medical device for improving high-frequency characteristics for skin aesthetics, comprising a multilayer printed circuit board based on a high dielectric constant insulating layer stack according to claim 3, and transmitting a high-frequency (RF) signal to the skin to perform cosmetic treatment, wherein the medical device for improving high-frequency characteristics comprises an RF electrode part, an RF oscillation and matching circuit part, a control processor and a temperature sensor part, wherein the control processor performs a real-time parameter adjustment function based on RF output intensity, treatment time, skin temperature, etc., and wherein the multilayer printed circuit board includes a temperature sensor and a feedback circuit that detect skin overheating for the safety of the user, and is manufactured based on a high dielectric constant ceramic / PTFE composite material to reduce RF loss and ensure treatment accuracy and temperature stability.

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