high heat dissipative metal PCB using CNT heat radiated coating

Abstract

The present invention relates to a high-heat dissipation metal PCB using a CNT heat dissipation coating. The present invention comprises: a copper foil layer (10) with a thickness of 35 to 210 mm; an epoxy insulating adhesive layer (20) with a thickness of 40 to 100 mm laminated on the lower part of the copper foil layer (10); an aluminum or copper sheet (30) with a thickness of 0.4 to 3 mm laminated on the lower part of the epoxy insulating adhesive layer (20); and a heat dissipation coating layer (40) laminated on the lower part of the aluminum or copper sheet (30) and made of any one of CNT, graphene, graphite, urethane, epoxy, silicone, acrylic, PVDF, and Teflon. According to the present invention, a heat dissipation coating layer is provided on the back aluminum sheet or copper sheet of a metal PCB, or a heat sink including a heat dissipation coating layer is provided, thereby enabling effective improvement of heat dissipation effect while preventing an increase in cost compared to conventional metal PCBs.

Description

Technology Field

[0001] The present invention relates to a high-heat dissipation metal PCB using a CNT heat dissipation coating, wherein a heat dissipation coating layer is provided on the back aluminum sheet or copper sheet of the metal PCB, or a heat sink including a heat dissipation coating layer is provided, thereby enabling effective improvement of heat dissipation effect while preventing cost increase compared to conventional metal PCBs. Background Technology

[0003] As shown in FIG. 1, the Metal PCB is a PCB using MCCL (Metal Copper Clad Laminate) having a structure in which a thermally conductive insulating adhesive (2) and aluminum or copper clad (3) are laminated under a copper foil layer (1) on which a circuit is formed.

[0004] These metal PCBs are developed for the purpose of efficiently dissipating heat generated by components such as LEDs and ICs, and are currently being applied in lighting, electronic products, automotive headlights, power semiconductors, and floodlights.

[0005] Currently, the metal PCB of the automobile is used as a heat sink in many applications, but in various applications related to lighting, a TIM (4) and a die-casting heat sink (5) are attached to the metal surface of the metal PCB to reinforce additional heat dissipation for high heat.

[0006] The epoxy adhesive used in metal PCBs performs three functions: improving thermal conductivity, electrical insulation, and adhesion.

[0007] The thermal conductivity of epoxy adhesives currently in general use in Korea is mainly 2 W / mk and 3.2 W / mk.

[0008] Epoxy adhesives with a high-performance thermal conductivity of 8.0 W / mk, which have superior heat dissipation performance compared to those with a thermal conductivity of 2 W / mk, are not widely used for economic reasons except for special applications because the price of the metal PCB substrate is 3 to 4 times higher.

[0009] Even epoxy adhesives with a thermal conductivity of 3.2 W / mk cost more than twice as much as those with 2 W / mk, and when actual heat dissipation performance is measured, the improvement in heat dissipation effect is limited to about 1.0 to 1.5°C.

[0010] As such, although the cost-effectiveness is poor, there are no other effective ways to improve heat dissipation performance, so 20% of the market uses epoxy adhesive with a thermal conductivity of 3.2 W / mk.

[0011] Meanwhile, the demand for heat dissipation due to autonomous driving, such as power semiconductors, has recently surged, and current metal PCBs can improve heat dissipation performance as follows.

[0012] First, high-performance specifications can be applied to epoxy adhesives.

[0013] For example, in the case of an epoxy adhesive with a thermal conductivity of 3.2 W / mk, the heat dissipation effect is improved by about 1.0 to 1.5°C, and in the case of an epoxy adhesive with a thermal conductivity of 8.0 W / mk, the heat dissipation effect is improved by about 3.0 to 3.5°C.

[0014] On the other hand, the heat dissipation effect can be improved by using a thicker material for the aluminum / copper sheet than currently used.

[0015] Finally, the simulant can be formed as a single piece without an epoxy adhesive layer, allowing a circuit to be implemented on one side for use.

[0016] However, the aforementioned improvement method has the problem of being significantly lacking in cost-effectiveness.

[0017] Regarding technology related to heat dissipation of metal PCBs, "Method for manufacturing a high-heat dissipation multilayer metal PCB" (Korean Registered Patent Publication No. 10-2161640, Patent Document 1) discloses a technology in which a ceramic insulator and a copper foil are repeatedly arranged on top of a heat sink and manufactured by applying heat and pressure, but the above Patent Document 1 has the problem that productivity is extremely poor. Prior art literature

[0019] KR 10-2161640 (2020.09.24) The problem to be solved

[0020] The high-heat dissipation metal PCB using the CNT heat dissipation coating of the present invention is intended to resolve the problems arising from the aforementioned conventional technology, and is designed to effectively improve heat dissipation effects while preventing an increase in cost compared to conventional metal PCBs by providing a heat dissipation coating layer on the back aluminum sheet or copper sheet of the metal PCB, or by providing a heat sink including a heat dissipation coating layer. means of solving the problem

[0022] To solve the above-mentioned problem, the high-heat dissipation metal PCB using the CNT heat dissipation coating of the present invention comprises: a copper foil layer (10) with a thickness of 35 to 210 mm; an epoxy insulating adhesive layer (20) with a thickness of 40 to 100 mm laminated on the lower part of the copper foil layer (10); an aluminum or copper sheet (30) with a thickness of 0.4 to 3 mm laminated on the lower part of the epoxy insulating adhesive layer (20); and a heat dissipation coating layer (40) laminated on the lower part of the aluminum or copper sheet (30) and made of any one of CNT, graphene, graphite, urethane, epoxy, silicone, acrylic, PVDF, and Teflon.

[0023] In the above configuration, between the aluminum or copper sheet (30) and the heat dissipation coating layer (40), a TIM (50) made of any one of a PCM sheet, heat dissipation tape (urethane / epoxy / rubber / silicone / acrylic), carbon fiber, silicone pad, thermal grease, liquid metal, heat dissipation gel, graphite sheet, graphene sheet, and heat dissipation adhesive; and a heat sink (60) having a heat dissipation coating treatment on any one of an aluminum plate, copper plate, magnesium sheet, and stainless steel sheet are continuously stacked downward.

[0024] Alternatively, it comprises: a copper foil layer (10) with a thickness of 35 to 210 mm; an epoxy insulating adhesive layer (20) with a thickness of 40 to 100 mm laminated on the lower part of the copper foil layer; an aluminum or copper sheet (30) with a thickness of 0.4 to 3 mm laminated on the lower part of the epoxy insulating adhesive layer (20); a TIM (50) laminated on the lower part of the aluminum or copper sheet and made of any one of a PCM sheet, thermal tape (urethane / epoxy / rubber / silicone / acrylic), carbon fiber, silicone pad, thermal grease, liquid metal, thermal gel, graphite sheet, graphene sheet, or thermal adhesive; and a heat sink (60) laminated on the lower part of the TIM and having a thermal coating treatment applied to any one of an aluminum plate, copper plate, magnesium sheet, or stainless sheet.

[0025] Alternatively, the device comprises: an integrated copper plate (70) having a circuit (71) formed on its upper surface; a TIM (50) laminated on the lower part of the copper plate (70) and made of any one of a PCM sheet, thermal tape (urethane / epoxy / rubber / silicone / acrylic), carbon fiber, silicone pad, thermal grease, liquid metal, thermal gel, graphite sheet, graphene sheet, or thermal adhesive; and a heat sink (60) laminated on the lower part of the TIM (50) and having a thermal coating treatment applied to any one of an aluminum plate, copper plate, magnesium sheet, or stainless steel sheet.

[0026] In the above configuration, the heat dissipation coating layer (40) is further provided, which is laminated on the lower part of the heat sink (60) and is made of any one of CNT, graphene, graphite, urethane, epoxy, silicone, acrylic, PVDF, and Teflon.

[0027] Alternatively, it comprises a copper foil layer (10) with a thickness of 35 to 210 mm; an integrated copper sheet (70) laminated on the lower part of the copper foil layer (10); and a heat dissipation coating layer (40) laminated on the lower part of the copper sheet (70) and made of any one of CNT, graphene, graphite, urethane, epoxy, silicone, acrylic, PVDF, and Teflon. Effects of the invention

[0029] According to the present invention, a heat dissipation coating layer is provided on the back aluminum sheet or copper sheet of a metal PCB, or a heat sink including a heat dissipation coating layer is provided, thereby enabling effective improvement of heat dissipation effect while preventing an increase in cost compared to conventional metal PCBs. Brief explanation of the drawing

[0031] Figure 1 is a drawing showing a conventional metal PCB structure. FIG. 2 is a drawing showing an example of a high heat dissipation metal PCB using the CNT heat dissipation coating of the present invention. FIG. 3 is a diagram showing an example of a metal PCB manufacturing process of the present invention. FIGS. 4 to 7 are drawings showing the heat dissipation test measurement process and results in the present invention. FIG. 8 is a diagram showing the state of the metal PCB after the chemical resistance measurement experiment in the present invention. FIG. 9 is a diagram showing the hardness test measurement results in the present invention. Specific details for implementing the invention

[0032] The high heat dissipation metal PCB using the CNT heat dissipation coating of the present invention is characterized by including a heat dissipation coating layer in the conventional metal PCB structure disclosed in FIG. 1.

[0033] Figure 2 illustrates several embodiments of the present invention for this purpose.

[0035] First, (A) of FIG. 2 is an example in which a copper foil layer (10), an epoxy insulating adhesive layer (20), an aluminum or copper sheet (30), and a heat dissipation coating layer (40) are formed continuously from top to bottom.

[0036] Figure 2 (B) is an example in which a TIM (50) and a heat sink (60) are continuously stacked downward between an aluminum or copper sheet (30) and a heat dissipation coating layer (40) in the structure of Figure 2 (A).

[0037] Also, (C) of FIG. 2 is an example in which a heat dissipation coating layer (40) is formed on the lower part of the heat sink (60) in the structure of (B) of FIG. 2.

[0038] Meanwhile, (D) of FIG. 2 is a structure in which an integrated simulant (70), TIM (50), and heat sink (60) are stacked from top to bottom.

[0039] Figure 2 (E) is an example in which a heat dissipation coating layer (40) is added to the lower part of the structure of Figure 2 (D).

[0040] (F) of FIG. 2 is a structure in which a copper foil layer (10), an integrated copper sheet (70), and a heat dissipation coating layer (40) are continuously stacked from top to bottom.

[0042] Figures 2 (E) and (F) are intended to improve upon Figure 1 (b), which uses a large and heavy aluminum die-casting heat sink attached to the back of the metal PCB metal layer for high heat dissipation in lighting and special transmission lights.

[0043] Conventional structures mostly use thermal grease with a thermal conductivity of 1.0 W / mk between the metal layer on the back of the metal PCB and the aluminum die-cast heatsink material, but after several months, cracks occur in the thermal grease due to the evaporation of oil, significantly reducing the heat dissipation effect and causing the LED lifespan to decrease rapidly.

[0044] Considering these points, using thermal gel or PCM sheet instead of thermal grease as the TIM (50) material is effective for improving heat dissipation.

[0046] In the above-described embodiments, it is preferable that the copper foil layer (10) has a thickness of 35 to 210 mm and the epoxy insulating adhesive layer (20) has a thickness of 40 to 100 mm.

[0047] The aluminum or copper sheet (30) is preferably 0.4 to 3 mm thick.

[0048] Aluminum or copper sheets (30) may also include chrome, nickel-plated and electrodeposited sheets.

[0049] Meanwhile, the heat dissipation coating layer (40) may be made of any one of the following materials: CNT, graphene, graphite, urethane, epoxy, silicone, acrylic, PVDF, and Teflon.

[0050] Also, TIM (50) can be made of any one of a PCM sheet, thermal tape, carbon fiber, silicone pad, thermal grease, liquid metal, thermal gel, graphite sheet, graphene sheet, or thermal adhesive.

[0051] At this time, the heat dissipation tape can be made of any one of urethane, epoxy, rubber, silicone, or acrylic.

[0052] In the above embodiments, it is preferable that the heat sink (60) be composed of a heat dissipation coating treatment applied to any one of the following materials: aluminum plate, copper plate, magnesium sheet, or stainless steel sheet.

[0054] A metal PCB with the above structure can be manufactured using a process as shown in Fig. 3.

[0055] Specifically, the aluminum sheet is cleaned by a dipping process to remove oil from the front and back surfaces, then a chromating layer is applied to a thickness of 1 micron to enhance corrosion resistance, then a heat dissipation coating layer is formed by a roll coating method and then cured.

[0056] Then, after preparing the copper foil, the aluminum sheet with the heat dissipation coating layer is laminated, and the product is inspected and cut.

[0057] The subsequent process can proceed through processes 1 to 12, in the same way as a conventional metal PCB manufacturing process.

[0059] Hereinafter, experimental examples of the present invention will be explained through FIGS. 4 to 7.

[0060] As shown in Fig. 4, a metal sheet with a heat dissipation coating on the aluminum sheet and the copper sheet on the back of the metal PCB was heat-laminated in a vacuum batch and then cut to size to produce a metal PCB, after which a heat dissipation test was conducted, divided into before and after the heat dissipation coating.

[0061] As a result, when tested with an input power of 30 Watts based on an average of 100mm X 100mm and 1.5T, an additional heat dissipation effect of an average of 8.5-10.0 degrees was achieved, significantly improving the most urgent additional heat dissipation performance of Metal PCBs, while maximizing cost-effectiveness to reduce costs by 30% and enabling an additional heat dissipation effect of approximately 8.0-8.5 degrees.

[0062] The experimental results can be explained in more detail as follows.

[0063] The first heat dissipation test was conducted on a finished metal PCB, divided into before and after the heat dissipation coating. The test was performed by supplying 30 Watts of power to a 175mm x 75mm, 1.5T size. As shown in Figure 5, an additional heat dissipation effect of approximately 4.6 degrees was confirmed after 40 minutes, and a difference of approximately 7.0 degrees was confirmed during a test of about 100 minutes.

[0064] The second heat dissipation test was conducted on aluminum metal PCB substrates (100mm X 100mm, 1.5T) with a heat dissipation coating before and after, at an input power of 30 Watts. As a result of testing a total of four samples, an additional heat dissipation effect of approximately 8.7-9.8 degrees was confirmed, as shown in Figure 6. Additionally, it was confirmed that the difference in heat dissipation effect between 2.0 Watts and 3.2 Watts epoxy adhesives was 1.0-1.5 degrees, indicating that although the substrate price is more than twice as expensive, the difference in heat dissipation effect is minimal.

[0065] The third heat dissipation test was conducted using a copper MCCL sheet (100mm X 100mm, 1.5T) with 30 Watts of input power, divided into tests before and after the heat dissipation coating, and as shown in Figure 7, an additional heat dissipation effect of approximately 8.9 degrees was achieved.

[0067] As can be seen from the experimental results above, we confirmed through testing with our client that using a thermal coating instead of using high-performance epoxy adhesive or increasing the weight of metal sheets on Metal PCBs to improve heat dissipation performance results in innovative cost reduction and an additional heat dissipation effect of 7.5-9.0 degrees compared to existing methods.

[0069] In addition, as shown in Figure 3, many chemicals are used in the metal PCB manufacturing process, and when applying a heat dissipation coating, the heat dissipation function can be performed only if it has chemical resistance and does not alter its physical properties.

[0070] Accordingly, the finished metal PCB product manufactured in the above experimental example was immersed in a 35% hydrochloric acid solution at a temperature of 50°C, removed after 10 minutes, and subjected to adhesion and corrosion tests.

[0071] The results are shown in Figures 8 and 9.

[0072] As can be seen in the photo of Fig. 8, it was confirmed that there was no visible corrosion, and it was confirmed that it has chemical resistance as a result of actual chemical resistance tests with the manufacturer.

[0073] In addition, the pencil hardness was measured and confirmed to be 2H, confirming that there was no change in physical properties.

[0075] Meanwhile, regarding the application of the heat sink (60) among the above embodiments, the heat sink made of conventional die-casting material has several problems.

[0076] More specifically, aluminum die casting materials consist of two types of alloys, ADC 10 and ADC 12, which have good structural and mechanical properties and account for about 98% of the die casting production volume. These materials are mainly composed of alloys of aluminum, copper, and silicon, with about 10 weight percent of silicon added.

[0077] Since this silicon is not a metal material, it reduces thermal conductivity.

[0078] Aluminum sheets (plates) produced by the actual rolling process have a thermal conductivity of 237 W / mk in the case of Aluminum 1050, whereas aluminum die-casting materials have a thermal conductivity of only 96 to 100 W / mk.

[0079] To address these issues, some studies have combined the heat dissipation fins and the heatsink body using laser welding, thereby constructing the heatsink body as a single-piece aluminum casting.

[0080] However, a key aspect of heat dissipation technology is minimizing air bubbles between the heat source and the heatsink; as mentioned above, in the case of conventional die-cast heatsinks, there was a problem where heat dissipation performance was reduced because air bubbles could not be minimized due to the reason that die-casting is performed to maximize heat dissipation by maximizing the air contact area, and because the heatsink manufacturer and the underlying component manufacturer are different.

[0081] To solve these problems, unlike die casting, a casting process in which molten metal is forcibly injected into a mold under high pressure, the heat sink is composed of plates, extruded materials, vapor chambers, or heat pipes with a maximized metal content having high thermal conductivity. This minimizes weight and volume compared to die casting materials, and by bonding surfaces with the lower attachments and interfacial bonding to minimize air gaps, it is possible to apply a heat sink with superior heat dissipation performance relative to the same weight and volume by minimizing the number of layers compared to conventional methods.

[0082] For example, when using a heat sink manufactured by press-forming pure aluminum extrusion, the heat dissipation effect can be maximized while reducing weight and volume by more than 50% compared to an aluminum die-cast heat sink.

[0083] Such a heat sink can be manufactured by preparing an aluminum plate, cleaning the front and back surfaces of the plate using a dipping process, coating it with chromate for corrosion prevention, applying a CNT heat dissipation coating material via a roll coating method and curing it, cutting it to fit the product shape, press-forming it, and then bending the sides as needed.

[0084] As another method to minimize the air gap, the air gap can be effectively suppressed by applying the above TIM as a heat dissipation gel or PCM sheet. Explanation of the symbols

[0086] 1 : Copper foil layer 2 : Insulating adhesive 3: Aluminum or simulant 4 : TIM 5 : Heatsink 10: Copper layer 20: Epoxy insulating adhesive layer 30: Aluminum or copper sheet 40 : Heat dissipation coating layer 50 : TIM 60 : Heatsink 70 : Integrated simultaneous die 71 : Circuit

Claims

Claim 1 A high-heat dissipation metal PCB comprising: a copper foil layer (10) having a thickness of 35 to 210 mm; an epoxy insulating adhesive layer (20) having a thickness of 40 to 100 mm laminated on the lower portion of the copper foil layer (10); an aluminum or copper sheet (30) having a thickness of 0.4 to 3 mm laminated on the lower portion of the epoxy insulating adhesive layer (20); and a heat dissipation coating layer (40) laminated on the lower portion of the aluminum or copper sheet (30) and made of any one of CNT, graphene, graphite, urethane, epoxy, silicone, acrylic, PVDF, and Teflon; a high-heat dissipation metal PCB using a CNT heat dissipation coating. Claim 2 A high-heat dissipation metal PCB using CNT heat dissipation coating, characterized in that, in the first aspect, between the aluminum or copper sheet (30) and the heat dissipation coating layer (40), a TIM (50) made of any one of a PCM sheet, a heat dissipation tape (urethane / epoxy / rubber / silicone / acrylic), a carbon fiber, a silicone pad, a thermal grease, a liquid metal, a heat dissipation gel, a graphite sheet, a graphene sheet, and a heat dissipation adhesive; and a heat sink (60) having a heat dissipation coating treatment on any one of an aluminum plate, a copper plate, a magnesium sheet, or a stainless steel sheet are continuously stacked downward. Claim 3 A high-heat dissipation metal PCB comprising: a copper foil layer (10) with a thickness of 35 to 210 mm; an epoxy insulating adhesive layer (20) with a thickness of 40 to 100 mm laminated below the copper foil layer; an aluminum or copper sheet (30) with a thickness of 0.4 to 3 mm laminated below the epoxy insulating adhesive layer (20); a TIM (50) laminated below the aluminum or copper sheet and composed of any one of a PCM sheet, thermal tape (urethane / epoxy / rubber / silicone / acrylic), carbon fiber, silicone pad, thermal grease, liquid metal, thermal gel, graphite sheet, graphene sheet, and thermal adhesive; and a heat sink (60) laminated below the TIM and having a thermal coating treatment applied to any one of an aluminum plate, copper plate, magnesium sheet, or stainless sheet. Claim 4 A high-heat dissipation metal PCB using CNT heat dissipation coating, comprising: an integrated copper plate (70) having a circuit (71) formed on its upper surface; a TIM (50) laminated below the copper plate (70) and made of any one of a PCM sheet, heat dissipation tape (urethane / epoxy / rubber / silicone / acrylic), carbon fiber, silicone pad, thermal grease, liquid metal, heat dissipation gel, graphite sheet, graphene sheet, and heat dissipation adhesive; and a heat sink (60) laminated below the TIM (50) and having a heat dissipation coating treatment applied to any one of an aluminum plate, copper plate, magnesium sheet, and stainless sheet. Claim 5 A high-heat dissipation metal PCB using a CNT heat dissipation coating, characterized in that, in claim 4, a heat dissipation coating layer (40) is further provided, which is laminated on the lower part of the heat sink (60) and is made of any one of CNT, graphene, graphite, urethane, epoxy, silicone, acrylic, PVDF, and Teflon. Claim 6 A high-heat dissipation metal PCB using a CNT heat dissipation coating, comprising: a copper foil layer (10) with a thickness of 35 to 210 mm; an integrated copper sheet (70) laminated on the lower part of the copper foil layer (10); and a heat dissipation coating layer (40) laminated on the lower part of the copper sheet (70) and made of any one of CNT, graphene, graphite, urethane, epoxy, silicone, acrylic, PVDF, and Teflon.

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