Manufacturing Method of a Boss Embedded Copper Clad Plate and a PCB Board

Abstract

The present application relates to a manufacturing method of a boss-embedded copper plate and a PCB board. The method includes: S1, manufacturing a copper plate; S2, pre-attaching a dry film: attaching a dry film at a preset position on the surface of the copper plate; S3, pattern transfer; S4, etching: etching the copper plate in S3, wherein 20%-25% of the reserved boss depth is not etched; S5, mechanical depth control removal: mechanically removing the remaining 20%-25% of the unetched boss on the copper plate in S4, and simultaneously cutting the etched boss according to the size of the boss to be manufactured, so that the corners of the cut boss are 90°; S6, assembly. The manufacturing method of the boss-embedded copper plate provided by the present application can make the corners of the cut boss be 90° after mechanical depth control removal, thereby solving the problem that the bottom of the boss has a curvature and is not perpendicular, and avoiding the phenomenon that protrusions will occur after the FR4 board is matched with the copper plate boss.

Description

Technical Field

[0001] The present invention relates to the technical field of printed circuit board manufacturing, and in particular to a method for manufacturing a boss-embedded copper plate and a PCB board. Background Art

[0002] At present, with the rapid development of high-frequency receivers and high-power module power supplies, the assembly density and integration of PCB components have increased, and the signal transmission speed has increased, power consumption has increased accordingly, and the requirements for heat dissipation and high-frequency transmission of PCB boards have become increasingly higher. High-frequency copper substrates are widely used in various types of metal-based printed circuit boards due to their excellent heat dissipation performance, good electromagnetic shielding performance, high mechanical strength and toughness, and small warpage and high dimensional stability.

[0003] A common copper substrate structure involves attaching a copper substrate to the back of a printed circuit board (PCB) to meet its heat dissipation requirements. In actual use, an insulating medium is placed between the power components and the copper substrate, and the overall heat dissipation performance of the copper-based PCB is affected by the heat dissipation performance of the insulating medium. However, the heat dissipation performance of existing insulating media is far inferior to that of copper-based materials, which affects the heat dissipation performance of the copper substrate. This, in turn, causes heat to accumulate on the PCB and prevents it from being effectively dissipated to the outside, significantly shortening the PCB's service life.

[0004] The existing process flow for producing copper layer bosses on circuit boards generally produces bosses with a depth of less than 0.3mm. For deeper boss designs, the bottom of the bosses produced by the existing process flow will have a severe slope, such as Figure 1 As shown, the deeper the depth, the worse the uniformity of the entire board, which affects the FR4 board that matches it. At the same time, there will be bulges on the surface after assembly. Summary of the Invention

[0005] Based on this, it is necessary to provide a method for manufacturing a boss embedded copper plate and a PCB board to address the problem that the existing process produces bosses larger than 0.5 mm and has a slope at the bottom.

[0006] The present application provides a method for manufacturing a boss-embedded copper plate, the method comprising:

[0007] S1. Making copper plate: Select T2 copper plate and roughen the surface of the copper plate;

[0008] S2. Pre-sticking dry film: sticking dry film on a preset position on the surface of the copper plate, wherein the surface size of the dry film is larger than the surface size of the boss to be made;

[0009] S3, pattern transfer: transfer the pattern of the copper plate in S2, and bake the copper plate after pattern transfer;

[0010] S4, Etching: Etch the copper plate in S3, where 20%-25% of the reserved boss depth is not corroded;

[0011] S5, Mechanical Depth Control Removal: Mechanically remove the remaining 20%-25% of the unetched bosses on the copper plate in S4, and at the same time, cut the etched bosses according to the size of the bosses to be fabricated so that the corners of the cut bosses are 90°;

[0012] S6, Assembly: Press-fit the FR4 board with the copper plate in S5.

[0013] In one embodiment, applying a dry film at a preset position on the copper plate surface includes: setting the temperature of the dry film applying machine to 110°C ± 5°C, adjusting the pressure to 5-7 kg, and adjusting the speed to 1 m / min, and then applying a dry film at the preset position on the copper plate surface through the dry film applying machine.

[0014] In one embodiment, baking the copper plate after pattern transfer includes: setting the temperature during baking to 120°C ± 3°C and the time to 15-30 minutes for baking.

[0015] In one embodiment, etching the copper plate in S3, where 20%-25% of the reserved boss depth is not corroded, includes:

[0016] Etch the copper plate in at least three times, and the depth of the boss after the last etching is 75%-80%.

[0017] In one embodiment, the etching process in S4 uses an acidic etching process, and the etching solution is a hydrochloric acid and ammonium chloride system.

[0018] In one embodiment, fabricating the copper plate in S1 includes: cutting a large-sized T2 copper plate into a size suitable for production.

[0019] In one embodiment, roughening the surface of the copper plate includes: roughening the surface of the copper plate with an acidic solution and a needle brush.

[0020] In one embodiment, the milling groove on the FR4 board matches the cut boss in S5.

[0021] In one embodiment, the etching in S4 includes: using a film as a light-blocking design for the boss position, removing the dry film at other positions except the boss through development, etching the surface of the copper plate respectively by an acidic etching method, and removing the dry film on the boss after etching is completed.

[0022] The present application also provides a PCB board, and at least one circuit layer in the PCB board is made by using the manufacturing method of the boss-embedded copper plate described in any one of the embodiments of the present application.

[0023] The beneficial effects of the present application include:

[0024] For the manufacturing method of the boss-embedded copper plate provided by the present application, after mechanical depth control and removal, the corners of the cut boss can be made to be 90°, thereby solving the problem of uneven boss height after the production of high-depth bosses, and at the same time solving the problem of the bottom of the boss having a non-perpendicular arc, and avoiding the phenomenon of protrusions generated after the FR4 board is matched with the copper plate boss. Description of the Drawings

[0025] Figure 1 It is a schematic diagram of a copper plate with a boss depth greater than 0.3 mm after etching in the existing copper plate;

[0026] Figure 2 It is a schematic flow chart of the manufacturing method provided by an embodiment of the present application;

[0027] Figure 3 It is a schematic diagram of a copper plate provided by an embodiment of the present application;

[0028] Figure 4 It is a schematic diagram of the copper plate provided by an embodiment of the present application after etching;

[0029] Figure 5 For Figure 4 It is a schematic diagram of the copper plate in after mechanical depth control and removal;

[0030] Figure 6 It is a schematic diagram of the FR4 board assembled to the Figure 5 copper plate in . Detailed Embodiments

[0031] To make the above objects, features, and advantages of the present application more obvious and understandable, the following will describe the detailed embodiments of the present application with reference to the accompanying drawings. Many specific details are set forth in the following description to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0032] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0033] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0034] In the present application, unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled", "fixed", etc. shall be construed broadly. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0035] In the present application, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "below", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0036] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are only for illustrative purposes and do not represent the only implementation.

[0037] The boss-embedded copper plate in this application is the PCB board (Printed Circuit Board), the Chinese name is printed circuit board, also known as printed wiring board, which is an important electronic component, a support for electronic components, and a carrier for the electrical connection of electronic components. The PCB board includes a circuit layer and a dielectric layer. The circuit layer includes circuits for conducting various electronic devices. In the PCB board, in the case of a large number of electronic devices, in order to prevent the conduction circuits between different electronic devices from affecting each other, multiple circuit layers are often provided. The dielectric layer is made of an insulating material and is used to isolate different circuit layers. The most common dielectric layer is the PP sheet (semi-cured sheet, a sheet-like bonding material synthesized from resin and a carrier). Generally speaking, the substrate of the PCB board has the same material as the dielectric layer. For the simplest-structured PCB board, there is only one dielectric layer and one or two circuit layers, and the surface of the circuit layer is treated with solder mask. For PCB boards with more layers, there may be multiple circuit layers and multiple dielectric layers arranged adjacent to each other, that is, the adjacent layers of the dielectric layer are circuit layers.

[0038] The existing overall production process of the PCB board includes: raw material preparation -> blanking -> inner layer pretreatment -> laminating -> exposure -> development -> etching -> stripping -> AOI inspection -> lamination -> drilling -> PTH -> outer layer pretreatment -> laminating -> exposure -> development -> graphic electroplating -> stripping -> outer layer etching -> tin stripping -> photosensitive solder mask -> surface treatment -> screen printing of text and marking symbols -> curing -> shape processing -> cleaning and drying treatment -> inspection and testing -> packaging of finished products. Among them, etching is a technology that removes materials by chemical reaction or physical impact.

[0039] Since there will be a very serious slope at the bottom of the boss produced by the existing process flow, to solve this problem, as Figure 2 shown, this application provides a method for manufacturing a boss-embedded copper plate, and the method includes:

[0040] S1. Manufacturing a copper plate: Select a T2 copper plate, and roughen the surface of the copper plate to roughen the surface of the copper plate;

[0041] S2. Pre-paste dry film: Paste a dry film at a preset position on the surface of the copper plate, and the surface size of the dry film is larger than the surface size of the boss to be fabricated.

[0042] S3. Pattern transfer: Perform pattern transfer on the copper plate in S2, and simultaneously perform baking on the copper plate after pattern transfer.

[0043] S4. Etching: Etch the copper plate in S3, where 20%-25% of the depth of the reserved boss is not corroded.

[0044] S5. Mechanical depth control removal: Mechanically remove the remaining 20%-25% of the unetched boss on the copper plate in S4, and simultaneously cut the etched boss according to the size of the boss to be fabricated, so that the corners of the cut boss are 90°.

[0045] S6. Assembly: Press-fit the FR4 board and the copper plate in S5.

[0046] Specifically, in this application, a T2 purple copper plate with a relatively high purity is selected as the material for fabricating the boss, which can fully meet the current requirements for the electrical conductivity and thermal conductivity of printed circuit boards; purple copper is copper with a very high copper content, and the total content of other impurities is less than 1%. Chemical composition of T1: copper + silver CuAg: ≥99.95, T2 purple copper: silver + copper + silver CuAg: ≥99.9, T3 chemical composition: copper + silver CuAg: ≥99.70. Red copper is pure copper, also known as purple copper. The density of pure copper is 8.96 and the melting point is 1083°C. It has excellent electrical conductivity and thermal conductivity, excellent plasticity, and is easy to be hot-pressed and cold-pressed. It can be widely used in products requiring good electrical conductivity.

[0047] Then, rough-treat the T2 purple copper plate with acid solution and needle brush to roughen the surface of the copper. After treating the copper plate, pre-paste a dry film on the surface of the copper plate. The surface size of the dry film is larger than the surface size of the boss to be fabricated. Set the temperature of the dry film pasting machine to 110°C ± 5°C, adjust the pressure to 5 - 7 kg, and adjust the speed to 1 m / min to make the dry film closely adhere to the copper surface.

[0048] Subsequently, perform pattern transfer on the above copper plate, as Figure 3 shown. The size of the boss pattern 11 on the pattern board 10 is larger than the size of the boss to be fabricated. For example: if the size of the boss to be fabricated is 10 mm and the depth is 1 mm, then the size of the boss pattern 11 on the pattern board 10 is greater than or equal to 11 mm. When the pattern is formed on the copper surface, bake the copper plate after pattern transfer. Set the temperature to 120°C ± 3°C and the time to 15 - 30 minutes during baking to cure the dry film on the surface of the copper, increase the bonding force between the dry film and the copper surface, and prevent peeling.

[0049] At this time, as Figure 4As shown, the copper plate 10 is etched while ensuring that 20%-25% of the reserved boss depth on the copper plate 10 is not corroded, that is, only 75%-80% of the depth is etched, and a boss 101 is formed on the copper plate 10. However, there is an arc-shaped slope at the bottom of the boss 101.

[0050] After the above etching, the depth of the boss on the copper plate still differs from the required depth by 20%-25%. At this time, the remaining 20%-25% of the unetched boss is removed by mechanical depth control. Taking the surface of the copper plate boss as the zero point, the length and width of the boss are the required dimensions, and the Z-axis downward depth control value (boss depth) is the required boss height. After setting, the overall copper plate is depth-controlled by the set pattern to remove the remaining 20%-25%, as Figure 5 shown, so that the edge of the boss 101 is cut vertically to achieve the production of high-depth bosses.

[0051] Finally, as Figure 6 shown, the FR4 board 12 is assembled onto the above copper plate 10 for lamination, and after lamination, the copper surface is flush with the surface of the FR4 board.

[0052] The method for manufacturing the boss-embedded copper plate provided by this application can make the corners of the cut boss be 90° after mechanical depth control removal, and at the same time ensure that the bottom of the boss is flat, thus solving the problem of uneven boss height after the production of high-depth bosses, and at the same time solving the problem of non-vertical arc at the bottom of the boss, and avoiding the phenomenon of protrusion after the FR4 board is matched with the copper plate boss.

[0053] In some embodiments, a dry film is pasted at a preset position on the surface of the copper plate in this application, including: setting the temperature of the dry film pasting machine to 110°C ± 5°C, adjusting the pressure to 5-7 kg, and adjusting the speed to 1 m / min, and then pasting the dry film at the preset position on the surface of the copper plate through the dry film pasting machine.

[0054] In some embodiments, the copper plate after pattern transfer in this application is subjected to baking treatment, including: setting the temperature during baking to 120°C ± 3°C and the time to 15-30 minutes for baking treatment.

[0055] In some embodiments, the copper plate in S3 in this application is etched, wherein 20%-25% of the reserved boss depth is not corroded, including: etching the copper plate at least three times, and the depth of the boss after the last etching is 75%-80%.

[0056] Exemplarily, as Figure 4 shown in Figure (a) of, 30% of the overall boss height is corroded for the first time, as Figure 4 shown in Figure (b) of, 30% of the overall boss height is corroded for the second time, as Figure 4 shown in Figure (c) of, and finally 15%-20% of the overall boss height is corroded.

[0057] In some embodiments, the etching process of S4 uses an acidic etching process, and the etching solution is a hydrochloric acid and ammonium chloride system.

[0058] In some embodiments, the production of the copper plate in S1 includes: cutting a large-sized T2 copper plate into a size suitable for production.

[0059] In some embodiments, the surface of the copper plate is roughened, including: roughening the surface of the copper plate with an acidic solution and a needle brush.

[0060] In some embodiments, the routing groove on the FR4 board is matched with the boss after cutting in S5.

[0061] In some embodiments, the etching in S4 includes: using a film for light blocking design at the position of the boss, removing the dry film at other positions except the boss through development, etching the surface of the copper plate by an acidic etching method respectively, and removing the dry film on the boss after etching.

[0062] The present application also provides a PCB board, and at least one circuit layer in the PCB board is made by the method for manufacturing a boss-embedded copper plate according to any one of the descriptions in the embodiments of the present application.

[0063] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0064] The above-described embodiments only represent several implementation manners of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A manufacturing method of a convex platform embedded copper plate, characterized in that, The method includes: S1. Making a copper plate: Select a T2 purple copper plate, roughen the surface of the copper plate to coarsen the surface of the copper plate; S2. Pre-attaching a dry film: Attach a dry film at a preset position on the surface of the copper plate, and the surface size of the dry film is larger than the surface size of the boss to be made; The attaching of the dry film at the preset position on the surface of the copper plate includes: Set the temperature of the dry film attaching machine to 110°C ± 5°C, adjust the pressure to 5 - 7 kg, and adjust the speed to 1 m / min, then attach the dry film at the preset position on the surface of the copper plate through the dry film attaching machine; S3. Graphic transfer: Perform graphic transfer on the copper plate in S2, and at the same time, perform baking on the copper plate after graphic transfer; S4. Etching: Etch the copper plate in S3, wherein 20% - 25% of the depth of the reserved boss is not corroded; S5. Mechanical depth control removal: Mechanically remove the remaining 20% - 25% of the unetched boss on the copper plate in S4, and at the same time, cut the etched boss according to the size of the boss to be made, so that the corners of the cut boss are 90°; S6. Assembly: Press-fit the FR4 board with the copper plate in S5.

2. The manufacturing method of the boss-embedded copper plate according to claim 1, wherein The performing of baking on the copper plate after graphic transfer includes: Set the temperature during baking to 120°C ± 3°C and the time to 15 - 30 minutes for baking.

3. The manufacturing method of the boss-embedded copper plate according to claim 1, characterized in that, The etching of the copper plate in S3, wherein 20% - 25% of the depth of the reserved boss is not corroded, includes: Etch the copper plate at least three times, and the depth of the boss after the last etching is 75% - 80%.

4. The manufacturing method of the boss-embedded copper plate according to claim 1, characterized in that, The etching process in S4 adopts an acidic etching process, and the etching solution is a hydrochloric acid and ammonium chloride system.

5. The manufacturing method of the boss-embedded copper plate according to claim 1, characterized in that The making of the copper plate in S1 includes: Cutting a large-sized T2 purple copper plate into a size suitable for production.

6. The manufacturing method of the boss-embedded copper plate according to claim 1, characterized in that, The roughening of the surface of the copper plate includes: Roughen the surface of the copper plate through an acidic solution and a needle brush.

7. The manufacturing method of the boss-embedded copper plate according to claim 1, characterized in that, The milling groove on the FR4 board is matched with the cut boss in S5.

8. The manufacturing method of the boss-embedded copper plate according to claim 1, characterized in that, The etching in S4 includes: Use a film to block the light at the position of the boss, remove the dry film at other positions except the boss through development, etch the surface of the copper plate respectively by an acidic etching method, and remove the dry film on the boss after etching is completed.

9. A PCB board, characterized in that, At least one layer of circuit layer in the PCB board is made by the method for making a boss-embedded copper plate according to any one of claims 1 - 8.

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