Circuit board and manufacturing method thereof

Abstract

The embodiment of the present application relates to the technical field of circuit board, and discloses a circuit board and a manufacturing method thereof, the circuit board comprising: a substrate, a first metal layer and an isolation part, the first metal layer is arranged on the first surface of the substrate, the first metal layer is provided with an isolation hole, the isolation hole penetrates the first metal layer along a first direction, wherein the first direction is the direction from the first surface of the substrate to the second surface of the substrate, and the first surface of the substrate faces away from the second surface of the substrate; the isolation part comprises a bottom part and a protruding part, the bottom part is arranged on the first surface of the substrate, the bottom part is located in the isolation hole, and a gap is formed between the bottom part and the inner wall of the isolation hole, the protruding part is connected with the end surface of the end of the bottom part away from the substrate, and the protruding part protrudes from the aperture of the isolation hole away from the substrate. Through the above mode, the present application can avoid the contact short circuit between the conductive first metal layer and the metal heat sink.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the technical field of circuit board, in particular to a circuit board and a manufacturing method thereof. BACKGROUND

[0002] The heat generated by the electronic components welded on the circuit board needs to be dissipated to the external environment in time to avoid the overheating of the electronic components and the occurrence of faults. The current circuit board is provided with a copper foil on the surface, the copper foil is attached to the heat-conducting mud laid on the surface of the metal heat sink, the copper foil transmits the heat of the circuit board to the metal heat sink through the heat-conducting mud, and the heat-conducting mud separates the copper foil from the metal heat sink to avoid the direct contact between the copper foil and the metal heat sink and the short circuit between the circuit board and the metal heat sink.

[0003] If the thickness of the heat-conducting mud is thin, or the circuit board is bent and deformed in the production and assembly process, the copper foil is in contact with the surface of the metal heat sink after penetrating through the heat-conducting mud, and the short circuit between the circuit board and the metal heat sink occurs. SUMMARY

[0004] In view of the above problems, the embodiment of the present application provides a circuit board and a manufacturing method thereof, which overcomes the above problems or at least partially solves the above problems.

[0005] To solve the above technical problems, one technical scheme adopted by the present application is to provide a circuit board, comprising: a substrate, a first metal layer and an isolation part, the first metal layer is arranged on a first surface of the substrate, the first metal layer is provided with an isolation hole, the isolation hole penetrates through the first metal layer along a first direction, wherein the first direction is a direction from the first surface of the substrate to a second surface of the substrate, the first surface of the substrate faces away from the second surface of the substrate; the isolation part comprises a bottom part and a protruding part, the bottom part is arranged on the first surface of the substrate, the bottom part is located in the isolation hole, and there is a gap between the bottom part and the inner wall of the isolation hole, the protruding part is connected with the end face of the end of the bottom part away from the substrate, and the protruding part protrudes from the hole opening of the isolation hole away from the substrate.

[0006] Optionally, a first insulating layer is further included, the first insulating layer is arranged on the side of the first metal layer away from the substrate, the first insulating layer plugs the hole opening of the isolation hole away from the substrate, the first insulating layer is provided with a through hole, and the protruding part protrudes from the first insulating layer after penetrating through the through hole.

[0007] Optionally, the circuit board further comprises a first protective layer, the first protective layer comprises a first part and a second part, the first part is arranged between the bottom part and the protruding part; a first window is arranged on the surface of the first insulating layer away from the first metal layer, the first window penetrates through the first insulating layer along the first direction, and the second part is filled in the first window.

[0008] Optionally, the first insulating layer fills the isolation hole.

[0009] Optionally, the number of isolation holes is four, the four isolation holes are arranged around the first metal layer, and the number of isolation portions is at least four, and at least one isolation portion is arranged in each isolation hole.

[0010] Optionally, the circuit board further comprises a second metal layer and a second protective layer, the second metal layer is arranged on the second surface of the substrate, and the second protective layer is arranged on the surface of the second metal layer away from the substrate.

[0011] Optionally, the circuit board further comprises a via hole, and the via hole penetrates the circuit board in the thickness direction of the circuit board.

[0012] To solve the above technical problems, another technical solution adopted by the present application is to provide a manufacturing method of a circuit board for manufacturing the above-mentioned circuit board, the method comprising:

[0013] Laying a metal layer on the first surface of the substrate;

[0014] Etching a ring-shaped through hole on the metal layer, the ring-shaped through hole separates the metal layer to form a first metal layer and a bottom portion located in the ring-shaped through hole;

[0015] Opening a leakage hole in the steel mesh, covering the steel mesh on the surface of the metal layer away from the substrate, aligning the leakage hole with the bottom portion, brushing a mixture of flux and solder powder on the side of the steel mesh away from the metal layer, and filling the leakage hole with the mixture of flux and solder powder;

[0016] After the mixture of flux and solder powder solidifies, a protruding portion is formed on the end face of the bottom portion away from the substrate, and the steel mesh is removed.

[0017] Optionally, before the step of covering the steel mesh on the first surface of the metal layer away from the substrate, the method further comprises:

[0018] Coating ink on the surface of the metal layer away from the substrate, and forming a first insulating layer after the ink solidifies.

[0019] Optionally, after the step of coating ink on the surface of the metal layer away from the substrate, and forming a first insulating layer after the ink solidifies, the method further comprises: performing surface treatment on the surface of the metal layer away from the substrate to form a first protective layer

[0020] The beneficial effect of the embodiment of the present application is that: different from the prior art, the circuit board provided by the embodiment of the present application comprises a substrate, a first metal layer and a separation part, the first metal layer is arranged on a first surface of the substrate, the first metal layer is provided with a separation hole, the separation hole penetrates the first metal layer along a first direction, wherein the first direction is a direction in which the first surface of the substrate faces a second surface of the substrate, and the first surface of the substrate faces away from the second surface of the substrate; the separation part comprises a bottom part and a protruding part, the bottom part is arranged on the first surface of the substrate, the bottom part is located in the separation hole, and a gap is formed between the bottom part and an inner wall of the separation hole, and the protruding part is connected with an end face of an end of the bottom part facing away from the substrate, and the protruding part protrudes from an aperture of the separation hole facing away from the substrate. The protruding part is used for supporting and protecting the circuit board, when the side of the circuit board provided with the protruding part is attached to the metal heat sink on which the heat-conducting mud is laid, when the circuit board extrudes the heat-conducting mud until penetrates the heat-conducting mud layer, the protruding part protruding from the separation hole first contacts the metal heat sink, so that the circuit board provided by the embodiment of the present application can meet the heat dissipation demand of the circuit board, and contact short circuit between the conductive first metal layer and the metal heat sink is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly introduced as follows. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can also be obtained by the drawings without creative labor for those skilled in the art.

[0022] Figure 1 is a cross-sectional view of a circuit board provided by the embodiment of the present application;

[0023] Figure 2 is a schematic view of the circuit board provided by the embodiment of the present application when the circuit board is arranged on a heat sink;

[0024] Figure 3 is a cross-sectional view of a substrate of a circuit board provided by the embodiment of the present application;

[0025] Figure 4 is a schematic view of a first metal layer of a circuit board provided by the embodiment of the present application;

[0026] Figure 5 is a schematic view of a first insulating layer of a circuit board provided by the embodiment of the present application;

[0027] Figure 6 is a schematic view of a steel mesh used in a manufacturing method of a circuit board provided by the embodiment of the present application;

[0028] Figure 7 is a flowchart of a manufacturing method of a circuit board provided by the embodiment of the present application;

[0029] Figure 8 is a flow chart of a method for manufacturing a circuit board according to another embodiment of the present application;

[0030] Figure 9 is a flow chart of a method for manufacturing a circuit board according to yet another embodiment of the present application. DETAILED DESCRIPTION

[0031] For the purpose of promoting an understanding of the principles of the application, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will, nevertheless, be understood that no limitation of the scope of the application is intended by the use of such specific language. The particular embodiments of the application described herein are shown by way of illustration, and it is contemplated that the application can be practiced with other embodiments. The application described herein is directed to overcoming one or more of the disadvantages set forth above.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for describing particular embodiments only and is not intended to be limiting of the application. The use herein of "including", "comprising", "having" and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

[0033] In the present embodiment, refer to Figure 1 and Figure 2The circuit board 100 includes a substrate 1, a first metal layer 2, and an isolation portion 3. The outer surface of the substrate 1 is made of an insulating material, such as fiberglass or resin. The first metal layer 2 is disposed on the first surface of the substrate 1 and serves to conduct electricity and dissipate heat. The first metal layer 2 has an isolation hole 21 that penetrates the first metal layer 2 along a first direction, wherein the first direction is the direction from the first surface of the substrate 1 toward the second surface of the substrate 1, and the first surface of the substrate 1 faces away from the second surface of the substrate 1. The isolation portion 3 includes a bottom 31 and a protrusion 32. The bottom 31 is disposed on the first surface of the substrate 1 and is located within the isolation hole 21. A gap exists between the bottom 31 and the inner wall of the isolation hole 21, which serves as an insulating gap between the first metal layer 2 and the bottom 31, preventing the first metal layer 2 from conducting electricity with the bottom 31. The protrusion 32 is connected to the end face of the bottom 31 facing away from the substrate 1. The protrusion 32 protrudes from the opening of the isolation hole 21 facing away from the substrate 1. The protrusion 32 is used to support and protect the circuit board 100. When the side of the circuit board 100 with the protrusion 32 is placed on the metal heat sink 200 covered with thermal conductive putty 201, when the circuit board 100 squeezes the thermal putty until it penetrates the thermal putty layer, the protrusion 32 protruding from the isolation hole 21 first contacts the metal heat sink 200, thereby preventing the conductive first metal layer 2 from short-circuiting with the metal heat sink 200.

[0034] It should be noted that substrate 1 can be a single-layer board or a multi-layer board. When substrate 1 is a single-layer board, for example, substrate 1 can be a single-layer board made of glass fiber; when substrate 1 is a multi-layer board, substrate 1 consists of conductive layers and insulating materials alternately laminated and bonded together, for example... Figure 3 As shown, substrate 1 includes a PP (prepreg) layer 1a, a glass fiber layer 1b, and a metal layer 1c. The PP (prepreg) layer 1a and the glass fiber layer 1b are insulating materials, and the metal layer 1c is a conductive layer. The number of PP (prepreg) layer 1a, glass fiber layer 1b, and metal layer 1c in substrate 1 is not limited and can be set according to actual needs.

[0035] To ensure sufficient insulation clearance between the bottom 31 and the inner wall of the isolation hole 21, further, in some embodiments, please refer to... Figure 4 The minimum distance s between the inner wall of the isolation hole 21 and the outer wall of the isolation part 3 is 0.5mm.

[0036] In this embodiment, the first metal layer 2 is a copper foil. In other embodiments, the first metal layer 2 may also be a metal foil made of an inert metal with good conductivity, such as silver or gold.

[0037] For the bottom 31 and the protrusion 32, in the present embodiment, in order to adapt to the manufacturing process flow of the circuit board 100 and save manufacturing cost, the bottom 31 is made of the same material as the first metal layer 2, and the protrusion 32 is formed after the tin paste solidifies. It can be understood that in other embodiments, the bottom 31 is not limited to a copper foil, the protrusion 32 is not limited to a tin paste, and the material of the bottom 31 and the protrusion 32 is not limited.

[0038] Please refer to Figure 1 and Figure 5 The circuit board 100 further comprises a first insulating layer 4, which is arranged on the side of the first metal layer 2 away from the substrate 1, and is used to cover the area of the first metal layer 2 that is not allowed to be soldered. In the present embodiment, the first insulating layer 4 is UV (ultraviolet) ink, which solidifies to cover part of the surface of the first metal layer 2, and also seals the hole of the isolation hole 21 away from the substrate 1. It can be understood that since the UV ink is liquid before solidification, part of the UV ink will flow into the gap between the bottom 31 and the inner wall of the isolation hole 21. When the gap between the bottom 31 and the inner wall of the isolation hole 21 is large, the UV ink will completely fill the gap between the bottom 31 and the inner wall of the isolation hole 21. The first insulating layer 4 further forms a through hole 41 after solidification, and the protrusion 32 protrudes from the first insulating layer 4 after passing through the through hole 41.

[0039] It can be understood that the first insulating layer 4 is not limited to be made of ink, and in other embodiments, the first insulating layer 4 can also be made of insulating materials such as thermosetting epoxy liquid.

[0040] The circuit board 100 usually needs to use soldering materials such as tin paste for connecting the electrodes of the connectors and the soldering pads of the circuit board 100, and the adhesion between the tin paste used for soldering and the metal is the molecular force generated by the metal bond between tin and metal. If a layer of oxide film is formed on the surface of the metal due to oxidation, the oxide film will hinder the formation of the metal bond. Based on this, further, in order to avoid oxidation of the surface of the bottom 31 and the first metal layer 2 made of metal material, which will affect the adhesion of the protrusion 32 made of tin paste to the bottom 31 and the soldering effect of the electronic components to the first metal layer 2, in the present embodiment, please refer to Figure 1 and Figure 5The circuit board 100 further comprises a first protective layer 5, the first protective layer 5 comprises a first part 51 and a second part 52, the first part 51 is arranged between the bottom 31 and the convex part 32, the first insulating layer 4 is provided with a first window 42, the first window 42 penetrates the first insulating layer 4 along the first direction, the first window 42 exposes the part of the first metal layer 2 that can be used for welding, and the second part 52 is filled in the first window 42. Specifically, the first protective layer 5 is a tin layer, and the first protective layer 5 is formed by tin spraying on the surface of the first metal layer 2 away from the substrate 1 and the surface of the bottom 31 away from the substrate 1.

[0041] In the embodiment, referring to Figure 4 and Figure 5 , in order to better support the circuit board 100 to avoid short circuit of the conductive surface of the circuit board 100 and the heat sink 200, specifically, the isolation hole 21 is located in the area where the first window 42 is provided, the number of the isolation hole 21 is four, and the four isolation holes 21 are arranged around the four exposed parts of the first metal layer 2 at the first window 42, and the number of the isolation part 3 is four, and one isolation part 3 is arranged in one isolation hole 21.

[0042] It can be understood that in other embodiments, the first protective layer 5 is not limited to the tin layer, and the first protective layer 5 can also be a layer of uniform nickel and gold formed by a gold plating process; or an organic film is formed on the surface of the first metal layer 2 away from the substrate 1 and the surface of the bottom 31 away from the substrate 1 by using an OSP (organic solderability preservative) process.

[0043] In the embodiment, referring to Figure 1 , the circuit board 100 further comprises a second metal layer 6, a second insulating layer 7 and a second protective layer 8, the second metal layer 6 is arranged on the second surface of the substrate 1, the second insulating layer 7 is arranged on the side of the second metal layer 6 away from the substrate 1, the second insulating layer 7 is provided with a second window, and the second protective layer 8 is arranged on the second window. The material selection and function of the second metal layer 6 are the same as those of the above-mentioned first metal layer 2, the material selection and function of the second insulating layer 7 are the same as those of the second part 52 of the first insulating layer 4, and the material selection and function of the second protective layer 8 are the same as those of the above-mentioned first protective layer 5, which will not be described herein again.

[0044] In the embodiment, referring to Figure 1 , Figure 4 and Figure 5The circuit board 100 is further provided with a via hole 9, which is used to connect the circuits of the conductive layers of the circuit board 100 and also plays a role of heat transfer. The via hole 9 is located in the solderable area of the first metal layer 2 and the second metal layer 6, i.e., the via hole 9 is located in the area where the first window 42 and the second window overlap, and the via hole 9 penetrates the circuit board 100 along the thickness direction of the circuit board 100, wherein the thickness direction of the circuit board 100 is parallel to the first direction, and the inner wall of the via hole 9 and the edge of the aperture of the via hole 9 located in the first metal layer 2 and the second metal layer 6 are covered with a conductive metal layer, and the number of the via holes 9 is multiple, and the multiple via holes 9 are arranged in rows and columns with equal intervals. Specifically, the conductive metal layer is a copper layer deposited on the inner wall of the via hole 9 and the edge of the aperture of the via hole 9 located in the first metal layer 2 and the second metal layer 6 through a copper deposition process, and the thickness of the copper layer is further thickened through a plating process. In this way, the first metal layer 2 and the second metal layer 6 are conductive through the conductive metal layer, so that the electronic components welded on the two surfaces of the circuit board 100 can be electrically connected.

[0045] It can be understood that the number of the via holes 9 is not limited and can be selected according to the actual structure arrangement of the circuit board 100.

[0046] In some other embodiments, the circuit board 100 is a single-sided board, i.e., the circuit board 100 is only provided with the first metal layer 2, so that the circuit board 100 does not need to connect the conductive layers through the via hole 9, and the circuit board 100 can use the via hole 9 with the inner wall not covered with the conductive metal layer as a mounting hole.

[0047] In the embodiment, please refer to Figure 1 The circuit board 100 further includes a heat-generating electronic component 10, which can be a MOSFET (field effect transistor), an IGBT (insulated gate bipolar transistor), or a diode, etc. The heat-generating electronic component 10 is arranged on the surface of the second protective layer 8 facing away from the second metal layer 6, and the pin 10a of the heat-generating electronic component 10 is welded to the second protective layer 8, so that the pin 10a of the heat-generating electronic component 10 is electrically connected to the circuit network formed by the first metal layer 2 and the circuit network formed by the second metal layer 6; the shell of the heat-generating electronic component 10 is attached to the second protective layer 8, and the heat generated by the heat-generating electronic component 10 when working can be transferred to the first metal layer 2 and the first protective layer 5 through the second protective layer 8, the second metal layer 6, the via hole 9, and the conductive metal layer covering the inner wall of the via hole 9 and the edge of the aperture of the via hole 9 located in the second metal layer 6 and the first metal layer 2.

[0048] Figure 2A schematic diagram of the circuit board 100 provided in the embodiment is set on the heat sink 200, the first surface of the heat sink 200 is paved with the heat-conducting mud 201, the heat sink 200 is made of aluminum, when the circuit board 100 is set on the heat sink 200, the area of the circuit board 100 with the first window 42 is attached to the heat-conducting mud 201 of the heat sink 200, when the circuit board 100 is fixed on the heat sink 200, the circuit board 100 compresses the heat-conducting mud 201. When the heat-generating electronic element 10 works, the heat generated can be transmitted to the first metal layer 2 and the first protective layer 5 through the second protective layer 8, the second metal layer 6, the via hole 9 and the conductive metal layer covering the inner wall of the via hole 9 and the edge of the aperture of the via hole 9 located at the second metal layer 6 and the first metal layer 2, and finally transmitted to the heat sink 200 by the heat-conducting mud 201; at the same time, due to the gap between the bottom 31 and the inner wall of the isolation hole 21, the bottom 31 is not conductive with the first metal layer 2, and the protruding part 32 is not conductive with the heat-generating element and other electronic components of the circuit board 100, and since the protruding part 32 protrudes from the outer surface of the circuit board 100, when the heat-conducting mud 201 between the circuit board 100 and the heat sink 200 is lost, the protruding part 32 is preferentially abutted on the surface of the heat sink 200, avoiding the direct contact between the conductive surface of the circuit board 100 and the heat sink 200, which causes the short circuit to ground of the circuit board 100. In practical application, since the surface of the circuit board 100 towards the heat sink 200 is also provided with other components, the height of the component shell 11 protruding from the surface of the circuit board 100 is greater than the height of the protruding part 32 protruding from the surface of the circuit board 100, in order to make the protruding part 32 still play the insulation protection role, the first surface of the heat sink 200 is provided with the accommodating groove 202, the accommodating groove 202 is used for accommodating each component shell 11 protruding from the surface of the circuit board 100.

[0049] The circuit board 100 provided by the embodiment of the present application comprises a substrate 1, a first metal layer 2 and an isolation part 3. The first metal layer 2 is arranged on a first surface of the substrate 1. The first metal layer 2 is provided with an isolation hole 21 which penetrates the first metal layer 2 along a first direction. The first direction is a direction in which the first surface of the substrate 1 faces a second surface of the substrate 1. The first surface of the substrate 1 faces away from the second surface of the substrate 1. The isolation part 3 comprises a bottom part 31 and a protruding part 32. The bottom part 31 is arranged on the first surface of the substrate 1 and located in the isolation hole 21. A gap is formed between the bottom part 31 and an inner wall of the isolation hole 21. The protruding part 32 is connected to an end surface of an end of the bottom part 31 which faces away from the substrate 1. The protruding part 32 protrudes from an aperture of the isolation hole 21 which faces away from the substrate 1. The protruding part 32 is used to support and protect the circuit board 100. When the circuit board 100 is arranged on a metal heat sink 200 on which heat-conducting mud 201 is laid and the circuit board 100 is pressed against the heat-conducting mud until it penetrates the heat-conducting mud layer, the protruding part 32 protruding from the isolation hole 21 first contacts the metal heat sink 200. Thus, the circuit board 100 provided by the embodiment of the present application can meet the heat dissipation requirement and avoid contact short circuit between the conductive first metal layer 2 and the metal heat sink 200.

[0050] The embodiment of the present application further provides a manufacturing method of the circuit board 100 for manufacturing the circuit board 100 described above. As shown in the figure, the method comprises the following steps. Figure 7

[0051] Step S101: laying a metal layer on a first surface of a substrate 1.

[0052] In the embodiment, the metal layer is a copper foil. The substrate 1 is immersed in resin. The copper foil is laid on the first surface of the substrate 1 and bonded together after heat pressing. Alternatively, a semi-cured sheet is stacked on the first surface of the substrate 1. The substrate 1 and the copper foil are bonded through the semi-cured sheet. Then, the semi-cured sheet is heat pressed and solidified through a press. The material of the metal layer can also be a metal with good conductive performance such as aluminum, gold or silver. The first surface of the substrate 1 can also form the metal layer through chemical deposition or electroplating.

[0053] Step S102: etching a ring-shaped through hole 41 on the metal layer. The ring-shaped through hole 41 separates the metal layer to form the first metal layer 2 and the bottom part 31 located in the ring-shaped through hole 41.

[0054] The shape of the ring-shaped through hole 41 is not limited. For example, the ring-shaped through hole 41 can be a circular ring or a square ring.

[0055] Step S105: opening a leakage hole 401 in a steel mesh 400. The steel mesh 400 is arranged on a surface of the metal layer which faces away from the substrate 1. The leakage hole 401 is aligned with the bottom part 31. A mixture of flux and solder powder is brushed on a side of the steel mesh 400 which faces away from the copper foil. The mixture of flux and solder powder fills the leakage hole 401.​

[0056] Wherein, the shape of the hole 401 is not limited, in the embodiment, the shape and size of the hole 401 is the same as the shape and size of the end surface of the end of the bottom 31 away from the substrate 1, the schematic diagram of the above steel mesh 400 and the hole 401 please refer to Figure 6 .

[0057] In the embodiment, the mixture of the flux and the solder powder is the tin paste, in some other embodiments, the solder powder can also use other fusible metals with lower melting point than the melting point of the soldered metal.

[0058] Step S106, after the mixture of the flux and the solder powder is solidified, the protruding part 32 is formed on the end surface of the end of the bottom 31 away from the substrate 1, and the steel mesh 400 is taken out.

[0059] Because in the current process of manufacturing the circuit board 100, including setting the conductive metal layer on the surface of the substrate 1, forming the circuit of the circuit board 100 on the metal layer on the surface of the substrate 1 by etching, in order to weld the electronic components, the tin paste is needed to be bonded on the metal layer through the steel mesh 400, therefore, through the above manufacturing method of the circuit board 100, it can be directly combined with the existing manufacturing method of the circuit board 100 without changing the manufacturing process, so as to save the production cost.

[0060] In some embodiments, before the step of covering the steel mesh 400 on the surface of the metal layer away from the substrate 1, as shown in Figure 8 , the method further comprises:

[0061] Step S103, coating the ink on the surface of the metal layer away from the substrate 1, and forming the first insulating layer 4 after the ink is solidified.

[0062] Specifically, a uniform UV (ultraviolet curing) ink is covered on the surface of the circuit board 100 provided with the metal layer by silk screen printing or spraying, and then the places needed to be welded on the metal layer and the surface of the bottom 31 away from the substrate 1 are exposed by exposure development or laser imaging, and the exposed part of the surface of the bottom 31 away from the substrate 1 is the through hole 41 of the first insulating layer 4.

[0063] In some embodiments, after the step of coating the ink on the surface of the metal layer away from the substrate 1, and forming the first protective layer 5 after the ink is solidified, as shown in Figure 9 , the method further comprises:

[0064] Step S104, surface treatment is performed on the surface of the metal layer away from the substrate 1 to form the first protective layer 5.

[0065] Specifically, the material of the first protective layer 5 can be metal such as tin or gold, or organic material. When the material of the first protective layer 5 is metal such as tin, the surface treatment method can be tin spraying process, tin sinking process or electroplating, etc.; or OSP (organic solderability preservative) process is used to grow an organic film on the surface of the clean metal layer by chemical method.

[0066] It should be noted that the preferred embodiments of the present application are given in the specification and drawings of the present application, but the present application can be implemented in many different forms and is not limited to the embodiments described in the specification. These embodiments are not additional limitations on the content of the present application, and the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive. Furthermore, the above technical features continue to be combined with each other to form various embodiments not listed above, which are all considered to be within the scope of the present application. Furthermore, those skilled in the art can make improvements or modifications based on the above description, and all these improvements and modifications shall fall within the scope of the appended claims of the present application.

Claims

1. A circuit board, characterized in that, include: substrate; A first metal layer is disposed on a first surface of the substrate. The first metal layer has an isolation hole that penetrates the first metal layer along a first direction, wherein the first direction is the direction from the first surface of the substrate toward the second surface of the substrate, and the first surface of the substrate faces away from the second surface of the substrate. An isolation portion includes a bottom and a protrusion. The bottom is disposed on a first surface of the substrate and is located inside the isolation hole. A gap exists between the bottom and the inner wall of the isolation hole. The protrusion is connected to the end face of the bottom facing away from the substrate and protrudes from the opening of the isolation hole facing away from the substrate. The protrusion is used to prevent the first metal layer from contacting the metal heat sink when the side of the circuit board with the protrusion is attached to a metal heat sink covered with thermally conductive putty.

2. The circuit board according to claim 1, characterized in that, It also includes a first insulating layer, which is disposed on the side of the first metal layer facing away from the substrate. The first insulating layer blocks the opening of the isolation hole facing away from the substrate. The first insulating layer is provided with a through hole, and the protrusion protrudes out of the first insulating layer after passing through the through hole.

3. The circuit board according to claim 2, characterized in that, It also includes a first protective layer, which comprises a first portion and a second portion, wherein the first portion is disposed between the bottom and the protrusion; A first window is formed on the surface of the first insulating layer facing away from the first metal layer. The first window penetrates the first insulating layer along the first direction, and the second portion fills the first window.

4. The circuit board according to claim 2, characterized in that, The first insulating layer fills the isolation hole.

5. The circuit board according to claim 1, characterized in that, The number of isolation holes is four, and the four isolation holes are arranged around the first metal layer. The number of isolation parts is at least four, and at least one isolation part is provided in each isolation hole.

6. The circuit board according to claim 1, characterized in that, It also includes a second metal layer and a second protective layer, the second metal layer being disposed on the second surface of the substrate, and the second protective layer being disposed on the surface of the second metal layer facing away from the substrate.

7. The circuit board according to any one of claims 1-6, characterized in that, It also includes vias that penetrate the circuit board along its thickness direction.

8. A method for manufacturing a circuit board, used to manufacture the circuit board as described in any one of claims 1-7, characterized in that, The method includes: A metal layer is deposited on the first surface of the substrate; An annular via is etched into the metal layer, the annular via separating the metal layer to form the first metal layer and the bottom located within the annular via; A perforation is made in the stencil, and the stencil is placed on the surface of the metal layer facing away from the substrate. The perforation is aligned with the bottom. A mixture of flux and solder powder is brushed onto the side of the stencil facing away from the metal layer, and the mixture of flux and solder powder fills the perforation. After the mixture of flux and solder powder solidifies, the protrusion is formed on the end face of the bottom facing away from the substrate, and the stencil is removed.

9. The method according to claim 8, characterized in that, Before the step of covering the metal layer onto the first surface facing away from the substrate with the steel mesh, the method further includes: Ink is applied to the surface of the metal layer facing away from the substrate, and the ink solidifies to form a first insulating layer.

10. The method according to claim 9, characterized in that, After the step of coating ink on the surface of the metal layer facing away from the substrate, and the ink solidifying to form the first insulating layer, the method further includes: performing surface treatment on the surface of the metal layer facing away from the substrate to form a first protective layer.

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