Method for improving heat dissipation of FR4 circuit board

Abstract

The invention provides a method for improving heat dissipation of an FR4 circuit board. The method for improving the heat dissipation of the FR4 circuit board comprises the following steps: obtaining a laminated FR4 composite core board; wherein the FR4 composite core plate is provided with a component mounting area; dense drilling operation is carried out on the installation area of the component, so that a specific heat dissipation area is formed in the thickness direction of the FR4 composite core board in a penetrating mode; performing copper deposition operation on the FR4 composite core board; performing modified heat-conducting ink hole plugging operation on the FR4 composite core board after the copper deposition operation so as to fill the modified heat-conducting ink in the specific heat dissipation area to obtain an FR4 composite core board A; and baking and curing the FR4 composite core board A, carrying out ceramic board grinding operation and outer layer circuit manufacturing, and finally carrying out resistance welding operation to obtain the FR4 circuit board. According to the method, the FR4 circuit board which is low in price and capable of ensuring that the overall thickness of the FR4 circuit board is not increased can be prepared, rapid heat dissipation of components is achieved, and the FR4 circuit board can better adapt to application of electronic products which are high in power and small in size.

Description

Technical Field

[0001] The present disclosure relates to the technical field of FR4 circuit board production, and in particular to a method for improving heat dissipation of FR4 circuit boards. Background Art

[0002] FR4, also known as epoxy glass fiber cloth substrate, is widely used as the main raw material for circuit boards because of its high mechanical strength, good electrical properties in dry and wet states, and good flame retardancy. However, as the size of electronic products becomes smaller and smaller, the size of circuit boards is also constantly compressed and reduced. When the power of electronic products increases, it is easy to cause excessive heat dissipation of circuit boards and affect the normal operation of electronic products.

[0003] At present, the methods for improving the heat dissipation of circuit boards on the market usually include: adding heat dissipation holes, burying copper blocks or plugging copper paste, among which plugging copper paste is the current mainstream method. As Chinese patent document No. CN112954902B discloses a method for plugging holes with copper paste on circuit boards, a plug hole is formed by drilling a hole on the circuit board, and the plug hole penetrates the circuit board along the stacking direction of the circuit board; then the copper paste is plugged into the plug hole by a scraper to achieve copper paste plugging of the circuit board, which not only improves the heat dissipation performance of the circuit board, but also ensures the fullness and uniformity of the copper paste plug hole.

[0004] However, in actual applications, although the additional copper paste plugging holes can improve the heat dissipation performance of the circuit board to a certain extent, for some high-power and small-volume electronic products, due to space limitations, components and circuit boards are prone to excessive heat during operation, which affects the operation of components. At this time, some scholars will propose to add cooling fans or apply high thermal conductivity layers around adjacent components. However, the additional cooling fans or the application of high thermal conductivity layers will cause the overall thickness of the FR4 circuit board to become thicker, which cannot better adapt to the application of high-power and small-volume electronic products. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a method for improving the heat dissipation of FR4 circuit boards which is low-cost, ensures that the overall thickness of the FR4 circuit boards does not become thicker, and achieves faster heat dissipation of components, so as to better adapt to the application of high-power and small-volume electronic products.

[0006] The purpose of this disclosure is achieved through the following technical solutions:

[0007] A method for improving heat dissipation of an FR4 circuit board comprises the following steps:

[0008] Obtaining a laminated FR4 composite core board; wherein the FR4 composite core board is formed with a component mounting area;

[0009] Drilling holes densely in the mounting area of ​​the components to form a specific heat dissipation area in the thickness direction of the FR4 composite core board;

[0010] Performing copper deposition operation on the FR4 composite core board;

[0011] Performing a modified thermal conductive ink plugging operation on the FR4 composite core board after the copper deposition operation, so as to fill the modified thermal conductive ink in the specific heat dissipation area, thereby obtaining a FR4 composite core board A;

[0012] Baking and curing the FR4 composite core board A;

[0013] Performing a ceramic grinding operation on the baked and cured FR4 composite core board A;

[0014] The outer layer circuit is manufactured on the FR4 composite core board A which has been subjected to the ceramic grinding operation to obtain the FR4 composite core board B;

[0015] The FR4 composite core board B is subjected to a solder resist operation to obtain the FR4 circuit board.

[0016] In one embodiment, the step of performing dense drilling operation on the mounting area of ​​the component includes the following specific steps:

[0017] A plurality of spaced, densely-spaced through micro-holes are drilled in the mounting area of ​​the component to form the specific heat dissipation area.

[0018] In one embodiment, the diameter of the dense through micro-holes is 0.3 mm to 1.0 mm, and / or the spacing between the dense through micro-holes is 0.1 mm to 0.5 mm.

[0019] In one of the embodiments, the FR4 composite core board is subjected to a modified thermal conductive ink plugging operation under the conditions of a vacuum degree of ≤150pa, a scraper speed of 100mm / s to 600mm / s, and a scraper angle of 5° to 15°.

[0020] In one embodiment, the baking and curing temperature is 150° C. to 180° C., and the time is 30 min to 60 min.

[0021] In one embodiment, the modified thermal conductive ink includes at least one of Bairou 5F-S and Bairou 5F-A.

[0022] In one embodiment, the ceramic grinding operation of the baked and cured FR4 composite core board A includes the following steps:

[0023] Applying ceramic brush to the FR4 composite core board A;

[0024] The FR4 composite core board A that has been subjected to a ceramic brush is ground.

[0025] In one embodiment, the grinding is performed 2 to 5 times, and the grinding speed is 1.0 m / min to 5.0 m / min.

[0026] In one embodiment, before performing the modified thermal conductive ink plugging operation on the FR4 composite core board after the copper deposition operation, the modified thermal conductive ink is subjected to a vacuum degassing operation.

[0027] In one embodiment, after the step of performing a ceramic grinding operation on the baked and cured FR4 composite core board A and before the step of performing an outer layer circuit manufacturing on the ceramic grinding operation on the FR4 composite core board A, the following steps are also included:

[0028] The FR4 composite core board A that has been baked and cured is subjected to burr removal and hole inspection operations.

[0029] Compared with the prior art, the present invention has at least the following advantages:

[0030] Since the FR4 composite core board is formed with a component installation area, and the component installation area is densely drilled, a specific heat dissipation area can be formed in the thickness direction of the component installation area. When the modified thermal conductive ink plugging operation is performed on the FR4 composite core board after the copper plating operation, the modified thermal conductive ink can be well filled in the specific heat dissipation area, thereby realizing the setting of the specific heat dissipation area for the component. In this way, while ensuring that the overall thickness of the FR4 circuit board does not become thicker, faster heat dissipation of the components is also achieved, so as to better adapt to the application of high-power and small-volume electronic products. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 A flow chart of a method for improving heat dissipation of an FR4 circuit board according to an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of the structure of the connection between the FR4 circuit board and components according to an embodiment of the present invention;

[0034] Figure 3 A cross-sectional view of a plugged hole according to another embodiment of the present invention;

[0035] Figure 4 for Figure 3 Cross-sectional slices of multiple reflows after plugging the hole;

[0036] Figure 5 A cross-sectional view of a cap-plated electroplated hole after plugging according to another embodiment of the present invention;

[0037] Figure 6 A schematic structural diagram of a scraper in one direction according to an embodiment of the present invention;

[0038] Figure 7 for Figure 6 A partial enlarged view of point A shown;

[0039] Figure numerals: 10, FR4 circuit board; 30, scraper; 31, rigid scraper; 311, rotating plane; 3111, rotating groove; 312, inclined surface; 32, rotating abutting deformation scraping roller; 33, first de-glue roller; 34, second de-glue roller; 35, third de-glue roller. DETAILED DESCRIPTION

[0040] In order to facilitate the understanding of the present disclosure, the present disclosure will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present disclosure are given in the drawings. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present disclosure more thoroughly and comprehensively understood.

[0041] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present disclosure. The terms used herein in the specification of the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0043] The present invention provides a method for improving the heat dissipation of an FR4 circuit board, comprising the following steps: obtaining a pressed FR4 composite core board; wherein the FR4 composite core board is formed with a mounting area for components; performing a dense drilling operation on the mounting area for components to form a specific heat dissipation area through-through in the thickness direction of the FR4 composite core board; performing a copper plating operation on the FR4 composite core board; performing a modified thermal conductive ink plugging operation on the FR4 composite core board after the copper plating operation to fill the modified thermal conductive ink in the specific heat dissipation area to obtain a FR4 composite core board A; baking and curing the FR4 composite core board A; performing a ceramic grinding operation on the baked and cured FR4 composite core board A; performing an outer layer circuit manufacturing on the FR4 composite core board A after the ceramic grinding operation to obtain a FR4 composite core board B; performing a solder resist operation on the FR4 composite core board B to obtain the FR4 circuit board.

[0044] The above-mentioned method for heat dissipation of FR4 circuit boards is that the FR4 composite core board is formed with a component installation area; and the component installation area is densely drilled, so that a specific heat dissipation area can be formed through the thickness direction of the component installation area. When the modified thermal conductive ink plugging operation is performed on the FR4 composite core board after the copper plating operation, the modified thermal conductive ink can be well filled in the specific heat dissipation area, thereby realizing the setting of the specific heat dissipation area for the components. In this way, while ensuring that the overall thickness of the FR4 circuit board does not become thicker, faster heat dissipation of the components is also achieved, so as to better adapt to the application of high-power and small-volume electronic products.

[0045] See also Figure 1 In order to better understand the technical solution and beneficial effects of the present disclosure, the present disclosure is further described in detail below in conjunction with specific embodiments. A method for improving heat dissipation of an FR4 circuit board in one embodiment includes some or all of the following steps:

[0046] S101, obtaining a laminated FR4 composite core board; wherein the FR4 composite core board is formed with a component mounting area.

[0047] Understandably, in order to solve the heat dissipation problem of high-power and small-volume electronic products, some scholars believe that aluminum substrates can be directly replaced with FR4 circuit boards, which is very helpful for the heat dissipation of high-power and small-volume electronic products. However, due to the higher cost of aluminum substrates compared to FR4 circuit boards, the purchase cost of consumers has increased, resulting in a shrinking market.

[0048] Therefore, finding a new FR4 circuit board with low price and high heat dissipation is the main research direction of most manufacturers. Therefore, in the present disclosure, the pressed FR4 composite core board is still used as the main substrate to ensure that a new FR4 circuit board with low price and high heat dissipation is prepared.

[0049] S102, performing a dense drilling operation on the mounting area of ​​the components to form a specific heat dissipation area through the thickness direction of the FR4 composite core board.

[0050] It can be understood that in actual applications, the connection between components and circuit boards often causes heat overload problems. Therefore, in the present disclosure, since the FR4 composite core board is formed with a component installation area; and the component installation area is subjected to dense drilling operations, a specific heat dissipation area can be formed through the thickness direction of the component installation area. When the modified thermal conductive ink plugging operation is performed on the FR4 composite core board after the copper plating operation, the modified thermal conductive ink can be well filled in the specific heat dissipation area, and the setting of the specific heat dissipation area of ​​the component is realized. In this way, while ensuring that the overall thickness of the FR4 circuit board will not become thicker, the components can also be dissipated faster to better adapt to the application of high-power and small-volume electronic products, so as to ensure that a low-priced FR4 circuit board with high heat dissipation and overall thickness of the FR4 circuit board will not become thicker is obtained.

[0051] S103, performing copper plating operation on the FR4 composite core board, so that dense through micro-holes in a specific heat dissipation area can be metallized, thereby achieving conduction between various layers of the FR4 composite core board.

[0052] S104, performing a modified thermal conductive ink plugging operation on the FR4 composite core board after the copper plating operation, so as to fill the modified thermal conductive ink in the specific heat dissipation area, and obtain a FR4 composite core board A.

[0053] It can be understood that since the modified thermally conductive ink has a certain fluidity, when the modified thermally conductive ink is scraped on a specific heat dissipation area, and since the specific heat dissipation area is set through in the thickness direction of the FR4 composite core board, when the FR4 composite core board is subjected to the modified thermally conductive ink plugging operation, the modified thermally conductive ink can be well filled and flowed into the specific heat dissipation area, so as to realize the modified thermally conductive ink plugging operation on the FR4 composite core board after the copper plating operation.

[0054] S105. The FR4 composite core board A is baked and cured so that the modified thermal conductive ink can be cured under high temperature conditions, that is, the modified thermal conductive ink is embedded in a specific heat dissipation area. In this way, it is better guaranteed that the overall thickness of the FR4 circuit board finally prepared will not become thicker, and the problem of the overall thickness of the FR4 circuit board becoming thicker due to the traditional method of adding a heat dissipation fan or coating a high thermal conductivity layer around adjacent components is effectively avoided.

[0055] S106, performing a ceramic grinding operation on the baked and cured FR4 composite core board A to effectively grind away the modified thermal conductive ink that overflows from the board surface of the FR4 composite core board A during the plugging process, thereby ensuring that the board surface of the FR4 composite core board A is clean and smooth.

[0056] S107, manufacturing an outer layer circuit for the FR4 composite core board A that has undergone the ceramic grinding operation to obtain a FR4 composite core board B, so as to complete the preparation of the final outer layer circuit.

[0057] S108, performing solder resist operation on the FR4 composite core board B to obtain the FR4 circuit board, so that the outer surface of the FR4 composite core board B can be covered with a protective solder resist ink layer, thereby achieving better protection for the FR4 circuit board to prevent the FR4 circuit board from being damaged by the external environment, thereby increasing the service life of the FR4 circuit board.

[0058] The above-mentioned method for heat dissipation of the FR4 circuit board is to perform dense drilling operations on the mounting area of ​​the components, so that a specific heat dissipation area can be formed through the thickness direction of the mounting area of ​​the components, such as Figure 2 As shown, when the modified thermal conductive ink plugging operation is performed on the FR4 composite core board after the copper plating operation, the modified thermal conductive ink can be well filled in the specific heat dissipation area, thereby realizing the setting of the specific heat dissipation area for the components. In this way, while ensuring that the overall thickness of the FR4 circuit board does not become thicker, the components can also be dissipated faster to better adapt to the application of high-power and small-volume electronic products, thereby ensuring that a low-priced FR4 circuit board with a high heat dissipation and a whole thickness that does not become thicker is obtained, so as to better adapt to the application of high-power and small-volume electronic products.

[0059] In one of the embodiments, the step of performing dense drilling operation on the mounting area of ​​the component includes the following specific steps: drilling a plurality of spaced dense through microholes in the mounting area of ​​the component to form the specific heat dissipation area, so that the plurality of spaced dense through microholes can be arranged in the mounting groove, so that the modified thermal conductive ink can be well filled in the dense through microholes at each interval under the action of gravity and external force, so as to ensure that a modified thermal conductive ink embedding part with high fullness and flatness is prepared, which not only ensures the heat dissipation performance of the specific heat dissipation area, but also facilitates the user to install components, and also ensures that the overall thickness of the FR4 circuit board finally prepared will not become thicker, so as to better adapt to the application of high-power and small-volume electronic products.

[0060] It can be understood that if a large-area single hole is directly drilled in the installation area of ​​the component, the modified thermal conductive ink has good fluidity, which makes it difficult to form and fix it in the large-area single hole, and there are problems such as uneven filling and easy bubbles; and drilling a large-area single hole is easy to cause the FR4 composite core board to break, resulting in a high scrap rate; if multiple large holes are drilled in the installation area of ​​the component, the amount of FR4 composite core board removed per unit area will be large, resulting in the problem of small-area FR4 composite core board still breaking during the drilling process. Therefore, in one of the embodiments, by controlling the aperture of the dense through micro-holes to 0.3mm~1.0mm, the spacing between each of the dense through micro-holes is 0.1mm~0.5mm, so that the area of ​​the multiple dense through micro-holes distributed in the installation groove is more suitable, on the one hand, the problem of the FR4 composite core board of a small area being easy to break during the drilling process is avoided; on the other hand, the heat dissipation performance of the FR4 circuit board is guaranteed; on the other hand, the problem of the modified thermal conductive ink being difficult to form and fix is ​​avoided.

[0061] It should be noted that in order to ensure that the FR4 circuit board has a high heat dissipation performance, it is usually matched with dense through micropores with small spacing and dense through micropores with small apertures, that is, to form a dense specific heat dissipation area. In this way, the FR4 circuit board is ensured to have a high heat dissipation performance per unit area, and the small area of ​​the FR4 composite core board is better guaranteed to be less likely to break during the drilling process. Although the dense specific heat dissipation area can effectively ensure that the drilling process is not prone to breakage, and also improve the heat dissipation performance of the FR4 circuit board, it causes the modified thermal conductive ink to have poor fluidity in each dense through micropore, mainly because the dense specific heat dissipation area is rougher than the general more sparse specific heat dissipation area, resulting in poor fluidity of the modified thermal conductive ink in the dense specific heat dissipation area. Therefore, in the present disclosure, by improving the formula of the modified thermal conductive ink, the modified thermal conductive ink includes at least one of Bairou 5F-S and Bairou 5F-A.

[0062] It can be understood that since Bairou 5F-S and Bairou 5F-A have excellent fluidity, electrical conductivity and thermal conductivity, the modified thermal conductive ink can be well filled in multiple dense through micropores under the action of the scraper, effectively avoiding the problem of poor fluidity of the modified thermal conductive ink caused by dense specific heat dissipation areas.

[0063] In this embodiment, Bairou 5F-S and Bairou 5F-A are both provided by Shenzhen Bairou New Materials Co., Ltd. In a preferred embodiment, the ratio of Bairou 5F-S to Bairou 5F-A is 2:1, so as to ensure that the modified thermal conductive ink has high heat dissipation performance and high fluidity, so that the modified thermal conductive ink can be well filled in the dense through micropores under the action of the scraper, effectively avoiding the problem of incomplete plugging of the dense through micropores and cracks in the modified thermal conductive ink in the dense through micropores after curing.

[0064] Specifically, when the ratio of Bairou 5F-S to Bairou 5F-A is 2:1, the following can be obtained: Figure 3 The cross-sectional slice of the plug hole shown in the figure shows that the fullness is 100%, and the obtained FR4 circuit board has no delamination and crack phenomenon after 10 reflow operations. For details, please refer to Figure 4 .

[0065] In one of the embodiments, the FR4 composite core board is subjected to a modified thermal conductive ink plugging operation under the conditions of a vacuum degree of ≤150pa, a scraper speed of 100mm / s to 600mm / s, and a scraper angle of 5° to 15°.

[0066] It can be understood that in order to prevent the modified thermal conductive ink from entering the air, the modified thermal conductive ink plugging operation is performed on the FR4 composite core board through a vacuum screen printer. Specifically, the vacuum degree of the vacuum screen printer is controlled to be ≤150pa, the scraper speed is 100mm / s~600mm / s, and the scraper angle is 5°~15°, so as to achieve the modified thermal conductive ink plugging operation on multiple dense through micropores of the FR4 composite core board.

[0067] It can also be understood that if the scraper speed is greater than 600 mm / s, some dense through micropores will not be fully plugged, and if the scraper speed is less than 100 mm / s, the production efficiency will be low. Therefore, in the present disclosure, by controlling the scraper speed to 100 mm / s to 600 mm / s, and using the scraper angle of 5° to 15°, the scraper can quickly scrape the modified thermal conductive ink into multiple dense through micropores to ensure that the modified thermal conductive ink filled in the dense through micropores will not have excessive bubbles, or leaks, or plugging holes. Defects such as offset.

[0068] In one of the embodiments, the scraper also includes a steel scraper and a soft scraping part, the soft scraping part is wrapped around the outer surface of the steel scraper, the steel scraper is movably arranged on the frame of the vacuum screen printer, and the steel scraper is tilted on the workbench of the vacuum screen printer, and the tilt angle is 5° to 15°, so as to achieve a more comprehensive scraping of the modified thermal conductive ink, which is conducive to the modified thermal conductive ink to better flow into a plurality of dense through micropores, and the added soft scraping part can be better deformed under the action of the outside. On the one hand, the soft scraping part can scrape the modified thermal conductive ink more comprehensively into a plurality of dense through micropores to avoid excessive modified thermal conductive ink remaining on the surface of the FR4 composite core board A, thereby reducing the difficulty of subsequent glue removal; on the other hand, the added soft scraping part can better adhere to the surface of the FR4 composite core board A during the scraping process, reducing the generation of bubbles caused by the gap between the steel scraper and the surface of the FR4 composite core board A during the scraping process, thereby avoiding the problem of bubbles that are easy to appear during the plugging process.

[0069] In the present disclosure, since the movable arrangement of the vacuum screen printer and the rigid scraper is a prior art, it is not described in detail in the present disclosure.

[0070] In one embodiment, the rigid scraper has an inclined surface, and the inclined angle between the inclined surface and the workbench of the vacuum screen printer is 5° to 15°, so that the rigid scraper and the workbench of the vacuum screen printer are tilted.

[0071] It can be understood that although the additional soft scraping part can scrape the modified thermal conductive ink into multiple dense through micropores more comprehensively, the modified thermal conductive ink has a certain viscosity, which causes the scraper 30 to get stuck easily during the scraping process. Figure 6 and Figure 7 As shown, in one of the preferred embodiments, the scraper 30 also includes a rotating abutting deformable scraping roller 32, and the rotating abutting deformable scraping roller 32 is arranged at the bottom of the inclined surface 312 of the rigid scraper 31. When the scraper 30 encounters a large resistance when scraping the modified thermal conductive ink with a higher viscosity, the rotating abutting deformable scraping roller 32 will rotate. In this way, the scraper 30 can be prevented from getting stuck during the scraping process, while ensuring that the rotating abutting deformable scraping roller 32 can more comprehensively scrape the modified thermal conductive ink into multiple dense through micropores to reduce the difficulty of subsequent glue removal and minimize the generation of bubbles, thereby ensuring the quality of the plugging holes.

[0072] It should also be noted that since the rotating abutment deformable scraper roller 32 is arranged at the bottom of the inclined surface 312 of the rigid scraper 31, the rotating abutment deformable scraper roller 32 can have good flexibility and sealing abutment during bidirectional scraping, so as to achieve more flexible and comprehensive scraping in both directions, so as to better ensure the fullness of the modified thermal conductive ink filling in multiple dense through micropores.

[0073] like Figure 6 and Figure 7 As shown, in one embodiment, a rotating plane 311 and an inclined surface 312 connected to each other are formed on one side of the rigid scraper 31 facing the workbench, the rotating plane 311 is located at the bottom of the inclined surface 312, and the rotating plane 311 is concave to form a rotating groove 3111, and the rotating abutting deformed scraping roller 32 is rotatably arranged in the rotating groove 3111, and at least partially protrudes from the rotating groove 3111, so that the rotating abutting deformed scraping roller 32 can flexibly rotate at the bottom of the inclined surface 312 of the rigid scraper 31, so that the scraper 30 has good flexibility and sealing abutment during bidirectional scraping, so as to achieve more flexible and comprehensive scraping in both directions, so as to better ensure the fullness of the modified thermal conductive ink filling in multiple dense through micropores.

[0074] It is worth mentioning that for traditional drilling, since the aperture of traditional drilling is relatively small, one-way scraping can better meet the fullness of the plugging hole. However, for dense specific heat dissipation areas, since multiple dense through micropores are relatively small, if one-way scraping is still used, there will be a problem of poor fullness of the plugging hole. Therefore, in the present disclosure, by rotating the abutting deformation scraping roller 32 and rotating it in the rotating groove 3111, and at least partially protruding from the rotating groove 3111, when using it, first use the scraper 30 to scrape the FR4 composite core board A in the forward direction, and then scrape it in the reverse direction, and repeat 3 to 5 times until the modified thermal conductive ink cannot be scraped into the dense through micropores, so that the modified thermal conductive ink can be completely filled in the multiple dense through micropores, so as to achieve full plugging of the dense specific heat dissipation area.

[0075] It can be understood that, since the modified thermal conductive ink has a certain viscosity, the rotating abutting deformed scraping roller 32 is prone to adhesion when scraping the modified thermal conductive ink into the dense through micropores. Therefore, in one embodiment, the scraper 30 also includes a degumming roller, which is rotatably arranged in the rotating groove 3111, and the degumming roller and the rotating abutting deformed scraping roller 32 rotate relative to each other, so that when the rotating abutting deformed scraping roller 32 rotates, it can drive the degumming roller to rotate, so that the modified thermal conductive ink adhered to the surface of the rotating abutting deformed scraping roller 32 can be removed under the action of friction, and fall back to the modified thermal conductive ink on the FR4 composite core board A, and then scraped by the scraper 30 into the dense through micropores, effectively avoiding the modified thermal conductive ink adhered to the rotating abutting deformed scraping roller 32 and reducing the utilization rate of the modified thermal conductive ink.

[0076] In one embodiment, there are multiple degumming rollers, each of which is arranged along the circumference of the rotating groove 3111 to achieve a more comprehensive cleaning and degumming effect on the rotating abutting deformable scraper roller 32, thereby better improving the utilization rate of the modified thermal conductive ink.

[0077] It can be understood that although adding a plurality of adhesive removal rollers can achieve a more comprehensive cleaning and adhesive removal effect on the rotating abutting deformed scraping roller 32, it will affect the flexibility of the rotating abutting deformed scraping roller 32. Figure 6 and Figure 7 As shown, in a preferred embodiment, there are three degumming rollers, namely the first degumming roller 33, the second degumming roller 34 and the third degumming roller 35. The first degumming roller 33 is located at the first end of the semicircular rotating groove 3111, the second degumming roller 34 is located at the second end of the middle of the semicircular rotating groove 3111; the third degumming roller 35 is located at the third end of the semicircular rotating groove 3111; in this way, on the premise of maximally ensuring the flexibility of the rotation of the rotating abutting deformable scraper roller 32 and the first degumming roller 33, the second degumming roller 34 and the third degumming roller 35, the more comprehensive cleaning and degumming effect of the rotating abutting deformable scraper roller 32 is also guaranteed to the greatest extent, so as to better ensure the utilization rate of the modified thermal conductive ink.

[0078] In one of the embodiments, the first deglue roller 33, the second deglue roller 34 and the third deglue roller 35 are respectively tangent to the rotating abutting deformable scraper roller 32, thereby ensuring a more comprehensive cleaning and deglueing effect of the rotating abutting deformable scraper roller 32 to the greatest extent, and ensuring the sensitivity of the first deglue roller 33, the second deglue roller 34 and the third deglue roller 35 to the rotation of the rotating abutting deformable scraper roller 32.

[0079] In one of the embodiments, the rotating abutting deformable scraping roller is a silicone roller to ensure that the rotating abutting deformable scraping roller has good sealing abutment properties to achieve more comprehensive scraping of the modified thermal conductive ink.

[0080] In one embodiment, the surface of the adhesive removal roller is coated with polytetrafluoroethylene. Since the friction coefficient of polytetrafluoroethylene is small, the adhesive removal roller has good wear resistance, thereby ensuring that the adhesive removal roller is not prone to wear when rubbing against the rotating abutting deformed scraping roller, thereby reducing the generation of impurities and improving the utilization rate of the modified thermal conductive ink.

[0081] In one of the embodiments, rotating rods are formed at both ends of the rotating abutting deformable scraper roller, and the rotating rods are rotatably set in the rotating grooves, which are semicircular rotating grooves to realize the rotating setting of the rotating abutting deformable scraper roller in the rotating grooves.

[0082] It can be understood that if the area of ​​the semicircular rotating groove convexly provided on the rotating abutting deformed scraping roller is too large, the gap between the rotating abutting deformed scraping roller and the semicircular rotating groove is likely to be large, causing the modified thermal conductive ink to easily enter the rotating groove and affect the rotation of the rotating abutting deformed scraping roller. Therefore, in one embodiment, the rotating abutting deformed scraping roller convexly extends 0.1cm to 2cm from the semicircular rotating groove to ensure that the height of the semicircular rotating groove convexly provided on the rotating abutting deformed scraping roller is relatively small. In this way, the rotating abutting deformed scraping roller can ensure the flexibility of the rotating abutting deformed scraping roller's bidirectional rotation and the utilization rate of the modified thermal conductive ink while satisfying the requirement of scraping the modified thermal conductive ink more comprehensively.

[0083] In one of the embodiments, the baking and curing temperature is 150°C to 180°C, and the time is 30min to 60min, so as to achieve the curing of the modified thermally conductive ink in multiple dense through micropores, thereby ensuring that the modified thermally conductive ink is not prone to cracks during the baking and curing process, and ensuring that the modified thermally conductive ink formed and fixed in multiple dense through micropores has high fullness, flatness and high heat dissipation.

[0084] In one of the embodiments, the ceramic grinding operation on the baked and cured FR4 composite core board A includes the following steps: ceramic brushing the FR4 composite core board A; and grinding the FR4 composite core board A after the ceramic brushing.

[0085] It can be understood that in actual applications, in order to ensure that a high-saturation modified thermal conductive ink can be obtained after plugging the holes, it is usually ensured that the modified thermal conductive ink used is excessive, and the excessive modified thermal conductive ink will overflow multiple dense through micropores, resulting in the FR4 composite core board A being subsequently baked and cured. The board surface of the FR4 composite core board A will be adhered with modified thermal conductive ink glue. Therefore, in the present disclosure, the FR4 composite core board A is firstly subjected to a ceramic brush to effectively clean off a large amount of modified thermal conductive ink glue blocks, and then the FR4 composite core board A that has been subjected to the ceramic brush is ground to more comprehensively remove the modified thermal conductive ink glue fragments to ensure that the board surface of the FR4 composite core board A is clean and smooth.

[0086] In one of the embodiments, the step of grinding the FR4 composite core board A after being brushed by a ceramic brush comprises the following specific steps: grinding the FR4 composite core board A by using a non-woven brush.

[0087] It can be understood that since there is less modified thermal conductive ink glue remaining in the FR4 composite core board A after being brushed by the ceramic brush, and most of it is modified thermal conductive ink glue fragments, if a ceramic brush is still used for grinding at this time, and the ceramic brush has strong rigidity, it is easy to cause scratches or damage to the FR4 composite core board A. Therefore, in the present disclosure, a non-woven brush with relatively weak rigidity is used to grind the FR4 composite core board A to ensure that the modified thermal conductive ink glue fragments are completely removed, while also reducing the chance of scratching the surface of the FR4 composite core board A, thereby ensuring that the FR4 composite core board A is not easily deformed.

[0088] Specifically, the grinding is performed 2 to 5 times at a grinding speed of 1.0 m / min to 5.0 m / min, so as to achieve a more comprehensive debonding of the FR4 composite core board A, thereby ensuring that the surface of the FR4 composite core board A is clean, flat and not deformed.

[0089] In one embodiment, the non-woven brush is a 800# non-woven brush, and the ceramic brush is a 800# ceramic brush, so that the surface of the FR4 composite core board A is more effectively ensured to be clean, flat and not deformed.

[0090] In one of the embodiments, before the modified thermal conductive ink plugging operation is performed on the FR4 composite core board after the copper plating operation, the modified thermal conductive ink is subjected to a vacuum degassing operation to effectively remove the bubbles in the modified thermal conductive ink, thereby ensuring that no bubbles are generated in the modified thermal conductive ink after the plugging operation.

[0091] In one embodiment, after the step of performing a ceramic grinding operation on the FR4 composite core board A that has been baked and cured, and before the step of making an outer layer circuit on the FR4 composite core board A that has been ceramic grinding, the following step is also included: performing a deburring and hole inspection operation on the FR4 composite core board A that has been baked and cured to avoid the presence of burrs in the modified thermal conductive ink after curing, which may affect the conductivity and heat dissipation.

[0092] like Figure 5 As shown, in one embodiment, after the step of deburring and inspecting the holes of the baked and cured FR4 composite core board A, and before the step of making the outer layer circuit of the FR4 composite core board A after the ceramic grinding plate operation, the following specific steps are also included: cap electroplating operation is performed on the modified thermal conductive ink after baking and curing to form a conductive connection bridge on the modified thermal conductive ink after baking and curing.

[0093] It can be understood that after the modified thermally conductive ink is baked and cured, it can be cured in the dense through micropores to form a modified thermally conductive ink embedded part. In this way, conductive connection bridges are formed at both ends of the modified thermally conductive ink embedded part, which is beneficial to the subsequent conduction with the outer layer circuit and the wiring of the outer layer circuit, thereby improving the utilization rate of the wiring per unit area and effectively avoiding the problem of low utilization rate of the wiring per unit area due to more windings during wiring of the outer layer circuit.

[0094] In one embodiment, the cap electroplating thickness is 12 μm to 15 μm.

[0095] Compared with the prior art, the present invention has at least the following advantages:

[0096] Since the FR4 composite core board is formed with a component installation area, and the component installation area is densely drilled, a specific heat dissipation area can be formed in the thickness direction of the component installation area. When the modified thermal conductive ink plugging operation is performed on the FR4 composite core board after the copper plating operation, the modified thermal conductive ink can be well filled in the specific heat dissipation area, thereby realizing the setting of the specific heat dissipation area for the component. In this way, while ensuring that the overall thickness of the FR4 circuit board does not become thicker, faster heat dissipation of the components is also achieved, so as to better adapt to the application of high-power and small-volume electronic products.

[0097] Some specific examples are given below, and if % is mentioned, it means percentage by weight. It should be noted that the following examples do not exhaust all possible situations, and the materials used in the following examples can be obtained from commercial sources unless otherwise specified.

[0098] The above-mentioned embodiments only express several implementation methods of the present disclosure, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the disclosed patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present disclosure, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the disclosed patent shall be subject to the attached claims.

Claims

1. A method for improving heat dissipation of FR4 circuit boards, characterized in that: The steps include: Obtaining a laminated FR4 composite core board; wherein the FR4 composite core board is formed with a component mounting area; Drilling holes densely in the mounting area of ​​the components to form a specific heat dissipation area in the thickness direction of the FR4 composite core board; Performing copper deposition operation on the FR4 composite core board; Performing a modified thermal conductive ink plugging operation on the FR4 composite core board after the copper deposition operation, so as to fill the modified thermal conductive ink in the specific heat dissipation area, thereby obtaining a FR4 composite core board A; Baking and curing the FR4 composite core board A; Performing a ceramic grinding operation on the baked and cured FR4 composite core board A; The outer layer circuit is manufactured on the FR4 composite core board A which has been subjected to the ceramic grinding operation to obtain the FR4 composite core board B; The FR4 composite core board B is subjected to a solder resist operation to obtain the FR4 circuit board.

2. The method for improving heat dissipation of FR4 circuit board according to claim 1, characterized in that: The step of performing dense drilling operation on the mounting area of ​​the components includes the following specific steps: A plurality of spaced, densely-spaced through micro-holes are drilled in the mounting area of ​​the component to form the specific heat dissipation area.

3. The method for improving heat dissipation of FR4 circuit board according to claim 2, characterized in that: The pore diameter of the dense through micropores is 0.3 mm to 1.0 mm; and / or, The spacing between the dense through micropores is 0.1 mm to 0.5 mm.

4. The method for improving heat dissipation of FR4 circuit board according to claim 1, characterized in that: The modified thermal conductive ink plugging operation is performed on the FR4 composite core board under the conditions of a vacuum degree of ≤150pa, a scraper speed of 100mm / s to 600mm / s, and a scraper angle of 5° to 15°.

5. The method for improving heat dissipation of FR4 circuit board according to claim 1, characterized in that: The baking and curing process is performed at a temperature of 150° C. to 180° C. and for a time of 30 min to 60 min.

6. The method for improving heat dissipation of FR4 circuit board according to claim 1, characterized in that: The modified thermal conductive ink includes at least one of Bairou 5F-S and Bairou 5F-A.

7. The method for improving heat dissipation of FR4 circuit board according to claim 1, characterized in that: The ceramic grinding operation of the baked and cured FR4 composite core board A includes the following steps: Applying ceramic brush to the FR4 composite core board A; The FR4 composite core board A that has been subjected to a ceramic brush is ground.

8. The method for improving heat dissipation of FR4 circuit board according to claim 7, characterized in that: The grinding is performed 2 to 5 times, and the grinding speed is 1.0 m / min to 5.0 m / min.

9. The method for improving heat dissipation of FR4 circuit board according to claim 1, characterized in that: Before performing the modified thermal conductive ink plugging operation on the FR4 composite core board after the copper deposition operation, the modified thermal conductive ink is subjected to a vacuum degassing operation.

10. The method for improving heat dissipation of FR4 circuit board according to claim 1, characterized in that: After the step of performing a ceramic grinding operation on the baked and cured FR4 composite core board A, and before the step of performing an outer layer circuit manufacturing on the ceramic grinding operation on the FR4 composite core board A, the following steps are also included: The FR4 composite core board A that has been baked and cured is subjected to burr removal and hole inspection operations.

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