Circuit board manufacturing method and circuit board

Abstract

The invention discloses a circuit board manufacturing method and a circuit board, and the method comprises the following steps: manufacturing a multi-layer board which comprises at least two overlapped substrate layers, and arranging conductor layers on the two sides of each substrate layer; processing an accommodating hole in the board surface of the multilayer board, wherein part of the hole wall of the accommodating hole is the conductor layer; copper paste is poured into the containing holes and solidified, so that the copper paste forms a conductive heat dissipation body, and the conductive heat dissipation body is communicated with the different conductor layers. The hole walls of part of the accommodating holes are the conductor layers, so that the conductive heat dissipation body not only can efficiently dissipate heat in the multilayer board, but also has a structure for conducting different conductor layers and forming an interlayer conductive network, copper blocks do not need to be processed according to the shapes of the accommodating holes, and the accommodating holes do not need to be electroplated to manufacture metalized hole walls, so that the manufacturing process is simplified, and the manufacturing cost is reduced. And the production cost is saved.

Description

Technical Field

[0001] The present invention relates to the field of circuit board processing, and in particular to a method for manufacturing a circuit board and a circuit board. Background Art

[0002] Some multi-layer circuit boards on the market, referred to as multi-layer boards, include a plurality of alternating conductor layers and substrate layers. In order to improve the internal heat dissipation capacity of the multi-layer board, a common solution is to process accommodation holes on the board surface of the multi-layer board and bury copper blocks and adhesive resins. The adhesive resin is used to bond the copper blocks to the multi-layer board, and the copper blocks can enhance the internal heat dissipation capacity of the multi-layer board. At present, some accommodation holes also play the role of connecting different conductor layers, so sometimes the hole walls of the accommodation holes are electroplated before burying the copper blocks to form metallized hole walls. The above-mentioned high heat dissipation circuit board has a relatively complex production process and a relatively high production cost. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a method for manufacturing a circuit board, which can simplify the manufacturing process and save production costs.

[0004] The present invention also provides a circuit board manufactured by the circuit board manufacturing method.

[0005] According to the first aspect of the present invention, a method for manufacturing a circuit board includes the following steps: preparing a multi-layer board, wherein the multi-layer board includes at least two superimposed substrate layers, and conductor layers are arranged on both sides of each substrate layer; processing a receiving hole on the board surface of the multi-layer board, and part of the hole wall of the receiving hole is the conductor layer; pouring copper paste into the receiving hole and curing the copper paste so that the copper paste forms a conductive heat sink, and the conductive heat sink conducts different conductive layers.

[0006] The method for manufacturing a circuit board according to the embodiment of the first aspect of the present invention has at least the following beneficial effects: by pouring copper paste into the receiving hole, the copper paste can automatically adapt to the shape of the receiving hole, and then the copper paste is solidified to form a conductive heat sink, and the conductive heat sink can be firmly combined with the hole wall of the receiving hole; and the hole wall of some of the receiving holes is a conductor layer, so the conductive heat sink can not only efficiently dissipate heat inside the multilayer board, but also has a structure of connecting different conductor layers to form an interlayer conductive network. There is no need to process copper blocks according to the shape of the receiving hole, and there is no need to electroplate the receiving hole to produce metallized hole walls, thereby simplifying the production process and saving production costs.

[0007] According to some embodiments of the present invention, the conductor layer is disposed at the bottom of the receiving hole.

[0008] According to some embodiments of the present invention, the accommodating hole has at least two hole bottom walls at different height positions, and the different hole bottom walls are formed by the conductor layers at different height positions.

[0009] According to some embodiments of the present invention, the method of processing the accommodating hole on the board surface of the multilayer board includes: cutting the accommodating hole of a predetermined depth at a predetermined position of the multilayer board, and then using a laser to remove the residual substrate layer in the accommodating hole and expose the conductor layer.

[0010] According to some embodiments of the present invention, after copper slurry is poured into the receiving hole and solidified, the method further includes: grinding one end of the conductive heat sink close to the opening of the receiving hole so that the one end of the conductive heat sink does not exceed the board surface of the multilayer board.

[0011] According to some embodiments of the present invention, a thermosetting resin is mixed in the copper paste, and the method of curing the copper paste includes: heating the copper paste to cure the thermosetting resin in the copper paste.

[0012] According to some embodiments of the present invention, the method of pouring copper paste into the receiving hole includes: stacking a screen printed board on the multilayer board, aligning a mesh area of ​​the screen printed board with the receiving hole, and using a scraper to scrape the copper paste on the screen printed board so that the copper paste passes through the mesh area and enters the receiving hole.

[0013] According to some embodiments of the present invention, the conductor layer is made of copper.

[0014] According to some embodiments of the present invention, both side surfaces of the multilayer board are the conductor layer, and after the copper paste is solidified, it also includes: etching the conductor layer on the board surface of the multilayer board to form a conductor heat dissipation part, and the conductor heat dissipation part is arranged around the opening of the accommodating hole.

[0015] The circuit board according to the embodiment of the second aspect of the present invention is manufactured by using the above-mentioned method for manufacturing a circuit board.

[0016] The circuit board according to the embodiment of the second aspect of the present invention has at least the following beneficial effects: since the above-mentioned method for manufacturing the circuit board is adopted, the manufacturing cost of the circuit board can be reduced and the manufacturing process can be simplified.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0019] Figure 1 It is a top view schematic diagram of a multilayer board after a receiving hole is opened in an embodiment of the present invention;

[0020] Figure 2 For the embodiment of the present invention Figure 1 A schematic cross-sectional view in the AA direction;

[0021] Figure 3 It is a top view schematic diagram of a conductive heat sink formed after the copper paste is cured on the multilayer board according to an embodiment of the present invention;

[0022] Figure 4 For the embodiment of the present invention Figure 3 A cross-sectional schematic diagram in the BB direction;

[0023] Figure 5 The figure is a complete flow chart of the method for manufacturing a circuit board according to an embodiment of the present invention.

[0024] Reference numerals:

[0025] Multilayer board 100, substrate layer 110, conductor layer 120, conductor heat dissipation portion 121, receiving hole 130;

[0026] The conductive heat sink 200 . DETAILED DESCRIPTION

[0027] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0028] In the description of the present invention, it should be understood that descriptions involving orientation, such as orientation or positional relationship indicated as up, down, etc., are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention 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 understood as a limitation on the present invention.

[0029] In the description of the present invention, "a plurality" means more than two. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0030] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0031] Some multilayer circuit boards on the market, referred to as multilayer boards 100, include a plurality of alternately stacked conductor layers 120 and substrate layers 110. In order to improve the internal heat dissipation capacity of the multilayer board 100, a common solution is to process accommodation holes 130 on the board surface of the multilayer board 100 and bury copper blocks and adhesive resins. The adhesive resin is used to bond the copper blocks to the multilayer board 100, and the copper blocks can enhance the internal heat dissipation capacity of the multilayer board 100. At present, some accommodation holes 130 also play the role of connecting different conductor layers 120, so sometimes the hole walls of the accommodation holes 130 are electroplated before the copper blocks are buried to form metallized hole walls. The above-mentioned high heat dissipation circuit board has a relatively complex production process and a relatively high production cost.

[0032] Another existing method for manufacturing a circuit board is to replace the copper block with a heat sink formed by solidifying the copper paste. However, in this manufacturing solution, electroplating is still performed in advance in the receiving hole 130 to form a metallized hole wall, and the manufacturing process is relatively complicated and the production cost is relatively high.

[0033] Reference Figure 5 , is a method for manufacturing a circuit board according to an embodiment of the present invention, comprising the following steps:

[0034] S10: preparing a multi-layer board 100, wherein the multi-layer board 100 includes at least two stacked substrate layers 110, and conductor layers 120 are disposed on both sides of each substrate layer 110;

[0035] S20: processing a receiving hole 130 on the board surface of the multilayer board 100, wherein a part of the hole wall of the receiving hole 130 is the conductor layer 120;

[0036] S30 : pouring copper paste into the receiving hole 130 and solidifying the copper paste to form a conductive heat sink 200 . The conductive heat sink 200 conducts different conductor layers 120 .

[0037] By pouring copper paste into the receiving hole 130, the copper paste can automatically adapt to the shape of the receiving hole 130, and then the copper paste is solidified to form a conductive heat sink 200, and the conductive heat sink 200 can be firmly combined with the hole wall of the receiving hole 130; and the hole wall of some of the receiving holes 130 is the conductor layer 120, so the conductive heat sink 200 can not only efficiently dissipate heat inside the multilayer board 100, but also has a structure of connecting different conductor layers 120 to form an interlayer conductive network. There is no need to process copper blocks according to the shape of the receiving hole 130, nor is there any need to electroplate the receiving hole 130 to produce a metallized hole wall, thereby simplifying the production process and saving production costs.

[0038] In the past, since the irregular-shaped receiving hole 130 requires an irregular-shaped copper block to fit, the machining difficulty of such an irregular-shaped copper block is relatively high, and the copper block may separate from the adhesive resin when heated and dissipated, thereby reducing the heat dissipation capacity. The conductive heat dissipation body 200 is formed by using copper slurry to flow into the receiving hole 130 and then solidify, so that the conductive heat dissipation body 200 has better adaptability to the shape of the receiving hole 130, thereby having better heat dissipation and conductive effects.

[0039] Furthermore, compared with the solution of pre-plating the receiving hole 130 to make a metallized hole wall and then curing the copper paste into the receiving hole 130, since the substrate layer 110 of the circuit board is made of resin, and the copper paste has a mixture of copper powder and thermosetting resin, the copper paste is directly poured into the receiving hole 130 and then cured. The thermosetting resin in the copper paste is directly combined with the resin of the substrate layer 110. Compared with the bonding of the resin to the smooth metallized hole wall, the direct bonding force between the resins is stronger, so that the cured conductive heat sink 200 is not easily separated from the hole wall of the receiving hole 130, thereby improving the heat dissipation stability of the circuit board under long-term high-temperature operation, that is, further improving the bonding strength between the conductive heat sink 200 and the multilayer board 100.

[0040] Specifically, the multilayer board 100 may be formed by stacking two, three, four or more substrate layers 110 , and each substrate layer 110 has a conductor layer 120 on both sides.

[0041] Reference Figures 1 to 4 In the embodiment, the bottom of the receiving hole 130 is provided with a conductor layer 120. After the copper paste in the receiving hole 130 is solidified to form the conductive heat sink 200, the conductor layer 120 forms the bottom wall of the receiving hole 130, so that the conductive heat sink 200 and the conductor layer 120 are connected and connected relatively stably, and the contact area between the conductor layer 120 and the conductive heat sink 200 is larger, so that the conductive heat sink 200 has a better heat dissipation capability.

[0042] In an embodiment, the accommodating hole 130 has two hole bottom walls at different height positions, and the different hole bottom walls are formed by the conductor layers 120 at different height positions. Therefore, two conductor layers 120 can simultaneously form the hole bottom wall of the accommodating hole 130, that is, two conductor layers 120 can simultaneously be in contact and connected with the conductive heat sink 200 over a large area, thereby having a better heat dissipation effect on the interior of the multilayer board 100, and making the conductive connection between each layer of the conductor layer 120 and the conductive heat sink 200 more stable.

[0043] Specifically, the receiving hole 130 may have two hole bottom walls, and in this case, two internal conductor layers 120 may respectively form the two hole bottom walls of the receiving hole 130. It is conceivable that the receiving hole 130 may also have three or more hole bottom walls, and in this case, three or more internal conductor layers 120 may respectively form the three hole bottom walls of the receiving hole 130. Those skilled in the art may make specific configurations according to actual needs.

[0044] It is understandable that, according to the requirements of setting the interlayer conductive network, part of the conductor layer 120 may not contact the hole wall of the receiving hole 130 to form an interlayer conductive network with different connection forms.

[0045] In an embodiment, in step S20, it includes:

[0046] S21 : cutting a receiving hole 130 of a predetermined depth at a predetermined position of the multilayer board 100 , and then using a laser to remove the remaining substrate layer 110 in the receiving hole 130 to expose the conductor layer 120 .

[0047] Usually, the substrate layer 110 is made of resin. The receiving hole 130 of a specified depth can be processed relatively accurately by cutting methods such as milling. The processing is relatively fast and low-cost. However, residual resin is likely to appear during the cutting process, which affects the conduction between the conductive heat sink 200 and the conductor layer 120. Subsequently, the residual resin in the receiving hole 130 is removed by laser to expose the conductor layer 120. The high temperature of the laser can remove the resin without easily damaging the conductor layer 120, so that the exposed conductor layer 120 is relatively intact, thereby improving the contact between the copper paste and the conductor layer 120.

[0048] In an embodiment, after step S30, the method further includes:

[0049] S40: Grind one end of the conductive heat sink 200 near the opening of the receiving hole 130 so that one end of the conductive heat sink 200 does not extend beyond the board surface of the multilayer board 100. Since the conductive heat sink 200 has good conductivity, when the circuit board is used, the conductor layer 120 may short-circuit with the outside through the conductive heat sink 200 extending beyond the board surface. Therefore, grinding away the conductive heat sink 200 extending beyond the board surface can reduce the risk of short-circuiting the circuit board.

[0050] In an embodiment, a thermosetting resin is mixed in the copper paste, and the method for curing the copper paste in step S30 includes:

[0051] S31: heating the copper paste to solidify the thermosetting resin in the copper paste.

[0052] The copper paste is an existing copper paste on the market, which has a mixture of copper powder and thermosetting resin. Since the copper paste has fluidity, the copper paste can flow relatively evenly in the irregular-shaped receiving hole 130, and can usually be cured after heating to form a conductive heat sink 200 that fits the irregular-shaped receiving hole 130.

[0053] In an embodiment, the method of pouring copper slurry into the receiving hole 130 in step S30 includes:

[0054] The screen printing plate is stacked on the multilayer board 100 , and the mesh area of ​​the screen printing plate is aligned with the receiving hole 130 . A scraper is used to scrape the copper paste on the screen printing plate so that the copper paste passes through the mesh area and enters the receiving hole 130 .

[0055] By repeatedly moving the scraper, the copper paste gradually flows into the receiving hole 130 through the mesh area, and finally fills the receiving hole 130. The process is relatively simple and the cost is low. Compared with the quantitative pouring method, the receiving hole 130 can be filled with copper paste. Specifically, the above copper paste pouring can be completed by a common screen printing machine without vacuum plugging. The screen printing machine is an existing device on the market and will not be described here.

[0056] In the embodiment, the receiving hole 130 penetrates part of the substrate layer 110. If the receiving hole 130 penetrates all the substrate layers 110, the structural strength of the multilayer board 100 may be reduced. Therefore, the receiving hole 130 penetrates part of the substrate layer 110 to reduce the impact of the opening of the receiving hole 130 on the structural strength of the circuit board.

[0057] In the embodiment, the conductor layer 120 is made of copper, which has good electrical and thermal conductivity and is suitable for manufacturing circuit boards.

[0058] In the embodiment, both sides of the multilayer board 100 are conductor layers 120, and after the copper paste is solidified in step S30, the following steps are further included:

[0059] S50: The conductor layer 120 on the board surface of the multilayer board 100 is etched to form a conductor heat dissipation portion 121, which is arranged around the opening of the receiving hole 130. A portion of the conductor layer 120 is etched away to form the conductor heat dissipation portion 121 arranged around the opening of the receiving hole 130, and an outer circuit area is formed at the same time, so that a larger heat dissipation area on the board surface of the multilayer board 100 can be reserved to form a larger heat dissipation channel, and a designated position of the outer circuit area on the board surface can be electrically connected to the conductive heat dissipation block by connecting the conductor heat dissipation portion 121, so that the conductor layers 120 between different layers can be electrically connected to each other; other positions of the circuit area are not directly connected to the conductor heat dissipation portion 121 to form a circuit effect.

[0060] Specifically, the method for preparing the multi-layer board 100 in step S10 is generally to press two or more inner layer boards together, and then perform electroplating on both side surfaces thereof to form the multi-layer board 100 .

[0061] Specifically, after step S40, the multilayer board 100 may be subjected to subsequent processes such as inspection, text printing, solder mask coating, surface treatment, cutting of the multilayer board 100, and electrical testing.

[0062] Specifically, the present invention also discloses a circuit board, which is manufactured by the above-mentioned circuit board manufacturing method. Due to the above-mentioned circuit board manufacturing method, the manufacturing cost of the circuit board can be reduced and the manufacturing process can be simplified.

[0063] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0064] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for manufacturing a circuit board, characterized in that: The following steps are involved: A multilayer board (100) is prepared, wherein the multilayer board (100) comprises at least two superimposed substrate layers (110), and conductor layers (120) are provided on both sides of each substrate layer (110); Processing a receiving hole (130) on the board surface of the multilayer board (100), wherein a portion of the hole wall of the receiving hole (130) is the conductor layer (120); Copper paste is poured into the receiving hole (130) and solidified to form a conductive heat sink (200) formed by the copper paste. The conductive heat sink (200) conducts the different conductor layers (120).

2. The method for manufacturing a circuit board according to claim 1, characterized in that: The conductor layer (120) is disposed at the bottom of the accommodating hole (130).

3. The method for manufacturing a circuit board according to claim 2, characterized in that: The accommodating hole (130) has at least two hole bottom walls at different height positions, and the different hole bottom walls are formed by the conductor layers (120) at different height positions.

4. The method for manufacturing a circuit board according to claim 2, characterized in that: The method for processing a receiving hole (130) on the board surface of the multilayer board (100) comprises: cutting and processing the receiving hole (130) of a predetermined depth at a predetermined position of the multilayer board (100), and then using a laser to remove the residual substrate layer (110) in the receiving hole (130) and expose the conductor layer (120).

5. The method for manufacturing a circuit board according to claim 1, characterized in that: After copper paste is poured into the receiving hole (130) and the copper paste is solidified, the method further comprises: grinding one end of the conductive heat sink (200) close to the opening of the receiving hole (130) so that the one end of the conductive heat sink (200) does not extend beyond the board surface of the multilayer board (100).

6. The method for manufacturing a circuit board according to claim 1, characterized in that: The copper paste is mixed with a thermosetting resin, and the method for curing the copper paste includes: heating the copper paste to cure the thermosetting resin in the copper paste.

7. The method for manufacturing a circuit board according to claim 1, characterized in that: The method for injecting copper paste into the receiving hole (130) comprises: stacking a screen printing plate on the multilayer board (100), aligning the mesh area of ​​the screen printing plate with the receiving hole (130), and using a scraper to scrape the copper paste on the screen printing plate so that the copper paste passes through the mesh area and enters the receiving hole (130).

8. The method for manufacturing a circuit board according to claim 1, characterized in that: The conductor layer (120) is made of copper.

9. The method for manufacturing a circuit board according to claim 1, characterized in that: Both sides of the multilayer board (100) are the conductor layer (120). After the copper paste is solidified, the method further comprises: etching the conductor layer (120) on the board surface of the multilayer board (100) to form a conductor heat dissipation portion (121), wherein the conductor heat dissipation portion (121) is arranged around the opening of the accommodating hole (130).

10. A circuit board, characterized in that: The circuit board is manufactured by the manufacturing method of any one of claims 1 to 9.

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