Circuit board and method for manufacturing the same

Abstract

A circuit board includes a circuit substrate, a first outer circuit layer, a second outer circuit layer and a heating element, wherein the circuit substrate is arranged between the first outer circuit layer and the second outer circuit layer. The circuit substrate includes a first inner circuit layer, a second inner circuit layer, a substrate layer, a plurality of heat-conducting columns and a heat-conducting agent, wherein the substrate layer is arranged between the first inner circuit layer and the second inner circuit layer, the heat-conducting columns are arranged on the first inner circuit layer at a distance, and a liquid storage space is provided between two adjacent heat-conducting columns, and the heat-conducting agent is filled in the liquid storage space. The first outer circuit layer is arranged on the heat-conducting columns, and there is a cavity between the first outer circuit layer and the heat-conducting agent, and the second outer circuit layer is arranged on the outer side of the second inner circuit layer. The circuit board is provided with a slot, which runs through the second outer circuit layer, the second inner circuit layer and the substrate layer, the first inner circuit layer is exposed at the bottom of the slot, and the heating element is installed at the bottom of the slot. In addition, the present application also provides a method for manufacturing a circuit board.

Description

Technical Field

[0001] The present application relates to a circuit board and a method for manufacturing the same. Background Art

[0002] The camera module includes a heating element (e.g., a sensor chip) and a circuit substrate, and the sensor chip is disposed on the circuit substrate. Generally, the heat generated by the sensor chip when it is working can be conducted and dissipated to the outside through the circuit substrate itself. However, as the circuit substrate becomes thinner and thinner and the number of functional electronic components increases, the circuit substrate itself has a large thermal resistance and the contact area between the circuit substrate and the photosensitive element is limited. Therefore, after long-term operation, the photosensitive chip is prone to temperature rise and heat is difficult to dissipate, and even causes the photosensitive element to burn out. Summary of the invention

[0003] In view of this, the present application provides a method for manufacturing a circuit board to improve the heat dissipation efficiency of a heat generating component.

[0004] In addition, it is also necessary to provide a circuit board manufactured by the above manufacturing method.

[0005] A method for manufacturing a circuit, comprising the steps of: providing a circuit substrate, the circuit substrate comprising a first inner circuit layer, a second inner circuit layer, a substrate layer, a plurality of heat-conducting columns and a heat-conducting agent, the substrate layer being arranged between the first inner circuit layer and the second inner circuit layer, the heat-conducting columns being arranged on the first inner circuit layer at a distance, a liquid storage space being provided between two adjacent heat-conducting columns, and the heat-conducting agent being filled in the liquid storage space. A first outer circuit layer is arranged on the heat-conducting columns, the first outer circuit layer enclosing the liquid storage space, a cavity being provided between the first outer circuit layer and the heat-conducting agent, and a second outer circuit layer is arranged on the second inner circuit layer to obtain an intermediate body. A first slot is arranged in the intermediate body, the first slot corresponds to the plurality of heat-conducting columns along the thickness direction of the intermediate body, the first slot penetrates the second outer circuit layer, the second inner circuit layer and the substrate layer, and the first inner circuit layer is exposed at the bottom of the first slot. A heating element is installed in the first slot to obtain the circuit board.

[0006] Furthermore, the manufacturing method of the circuit substrate includes: providing a copper-clad substrate, the copper-clad substrate including a first inner copper foil layer, a second inner copper foil layer, and a base material layer disposed between the first inner copper foil layer and the second inner copper foil layer. Disposing a dry film layer on the first inner copper foil layer, the dry film layer having a plurality of discretely distributed through holes. Electroplating in the through holes to form a plurality of the thermal conductive pillars. Removing the dry film layer, and etching the first inner copper foil layer to obtain the first inner circuit layer, etching the second inner copper foil layer to obtain the second inner circuit layer, and obtaining the circuit substrate.

[0007] Furthermore, the method for manufacturing the circuit substrate further includes: providing a covering layer on the first inner copper foil layer and the second inner copper foil layer.

[0008] Furthermore, the method further comprises the steps of: providing a second slot and a third slot on two opposite sides of the intermediate body, wherein the covering layer is exposed at the bottom of the second slot and the third slot.

[0009] Furthermore, the step of "arranging a first outer circuit layer on the thermally conductive column" includes: pressing a first outer copper foil layer on the thermally conductive column, and electroplating the first outer copper foil layer to form a first electroplating layer, and etching the first outer copper foil layer and the first electroplating layer to form the first outer circuit layer.

[0010] Furthermore, the step of "arranging a second outer circuit layer on the second inner circuit layer" includes: laminating a second outer copper foil layer on the second inner circuit layer, and electroplating the second outer copper foil layer to form a second electroplating layer, and etching the second outer copper foil layer and the second electroplating layer to form the second outer circuit layer.

[0011] Furthermore, the first outer copper foil layer includes a main body portion and a connecting portion, and the connecting portion is disposed between the main body portion and the heat conducting column.

[0012] Furthermore, the method further comprises the steps of: providing a metal layer in the first slot, and installing the heating element on the metal layer.

[0013] A circuit board comprises a circuit substrate, a first outer circuit layer, a second outer circuit layer and a heating element, wherein the circuit substrate is arranged between the first outer circuit layer and the second outer circuit layer, and the heating element is embedded in the second outer circuit layer and the circuit substrate.

[0014] The circuit substrate includes a first inner circuit layer, a second inner circuit layer, a base material layer, a plurality of heat-conducting columns and a heat-conducting agent. The base material layer is arranged between the first inner circuit layer and the second inner circuit layer. The heat-conducting columns are arranged on the first inner circuit layer at a distance. There is a liquid storage space between two adjacent heat-conducting columns, and the heat-conducting agent is filled in the liquid storage space.

[0015] The first outer circuit layer is disposed on the heat conductive column to close the liquid storage space, a cavity exists between the first outer circuit layer and the heat conductive agent, and the second outer circuit layer is disposed on the outer side of the second inner circuit layer.

[0016] The circuit board is provided with a groove, and along the thickness direction of the circuit board, the first groove corresponds to the plurality of the heat-conducting columns, the groove passes through the second outer circuit layer, the second inner circuit layer and the substrate layer, the first inner circuit layer is exposed at the bottom of the groove, and the heating element is installed at the bottom of the groove.

[0017] Furthermore, the thermal conductor is at least one of thermal oil, ammonia water and water.

[0018] The circuit board provided in the present application conducts the heat generated by the heating element to the thermal conductive agent by arranging the thermal conductive column, and forms heat convection with the help of the gas-liquid phase change of the thermal conductive agent, thereby improving the heat dissipation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the copper-clad substrate provided in an embodiment of the present application after a dry film layer is provided.

[0020] Figure 2 for Figure 1 Schematic diagram of the copper clad substrate after electroplating.

[0021] Figure 3 for Figure 2 Schematic diagram of the copper clad substrate after removing the dry film layer.

[0022] Figure 4 for Figure 3 The schematic diagram shown is a copper-clad substrate after etching to form a circuit layer.

[0023] Figure 5 for Figure 4 The schematic diagram of the copper-clad substrate after the peelable layer is provided is shown.

[0024] Figure 6 A schematic diagram of a circuit substrate provided in an embodiment of the present application.

[0025] Figure 7 This is a schematic diagram of the intermediate before lamination provided in an embodiment of the present application.

[0026] Figure 8 This is a schematic diagram of an intermediate provided in an example of the present application.

[0027] Fig. 9 for Figure 8 Schematic diagram of the intermediate body setup after electroplating is shown.

[0028] Fig.10 for Fig. 9 The intermediate body shown is a schematic diagram after the solder mask is set.

[0029] Fig.11 for Fig.10 The intermediate body shown is a schematic diagram after the first groove is set.

[0030] Fig.12 A schematic diagram of a circuit board provided in an embodiment of the present application.

[0031] Main component symbols

[0032] Circuit board 100

[0033] Circuit board 10

[0034] Copper clad substrate 101

[0035] First inner copper foil layer 102

[0036] Second inner copper foil layer 103

[0037] Opening 105

[0038] The first dry film layer 106

[0039] First through hole 1061

[0040] The second dry film layer 107

[0041] The second through hole 1071

[0042] First via 108

[0043] Covering layer 109

[0044] Adhesive layer 110

[0045] Peelable layer 111

[0046] The first inner wiring layer 11

[0047] The second inner wiring layer 12

[0048] Base material layer 13

[0049] Thermal Conductive Column 14

[0050] Liquid storage space 141

[0051] Cavity 142

[0052] Thermal Conductive Agent 15

[0053] The first copper foil layer 20

[0054] Main body part 21

[0055] Connecting part 22

[0056] First electroplating layer 23

[0057] First outer wiring layer 24

[0058] The second copper foil layer 30

[0059] The second electroplating layer 31

[0060] The second outer wiring layer 32

[0061] The first adhesive layer 40

[0062] Second adhesive layer 50

[0063] First slot 60

[0064] Metal layer 601

[0065] First groove 61

[0066] The second conductive body 611

[0067] Second groove 62

[0068] The third conductive body 621

[0069] The third through hole 63

[0070] Fourth conductive body 631

[0071] Solder mask 64

[0072] Second slot 65

[0073] The third slot 66

[0074] Heating element 70

[0075] Metal wire 71

[0076] Intermediate 200

[0077] Zone 1A

[0078] Zone 2B

[0079] Connection area C

[0080] Height

[0081] Depth D

[0082] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0083] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0084] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. When an element is considered to be "set on" another element, it may be directly set on the other element or there may be a central element at the same time.

[0085] See also Figures 1 to 12 The present invention provides a method for manufacturing a circuit board 100, the method comprising the steps of:

[0086] S1: Please see Figure 6 A circuit substrate 10 is provided, wherein the circuit substrate 10 includes a first inner circuit layer 11, a second inner circuit layer 12, a base material layer 13, a plurality of heat-conducting pillars 14 and a heat-conducting agent 15, wherein the base material layer 13 is arranged between the first inner circuit layer 11 and the second inner circuit layer 12, and the plurality of heat-conducting pillars 14 are arranged on the first inner circuit layer 11 at intervals, and a liquid storage space 141 is formed between each two adjacent heat-conducting pillars 14, and the heat-conducting agent 15 is filled in the liquid storage space 141.

[0087] In this embodiment, in step S1, see Figures 1 to 6 The manufacturing method of the circuit substrate 10 comprises the steps of:

[0088] S10: See Figure 1 A copper clad substrate 101 is provided, wherein the copper clad substrate 101 includes a first inner copper foil layer 102, a second inner copper foil layer 103, and a base layer 13, wherein the base layer 13 is disposed between the first inner copper foil layer 102 and the second inner copper foil layer 103. In this embodiment, the base layer 13 is made of polyimide (PI).

[0089] S11: an opening 105 is provided on the copper clad substrate 101 , wherein the opening 105 penetrates the second inner copper foil layer 103 and the base material layer 13 , and the first inner copper foil layer 102 is exposed at the bottom of the opening 105 .

[0090] S12: A first dry film layer 106 and a second dry film layer 107 are disposed on the copper clad substrate 101, wherein the first dry film layer 106 is disposed on the first inner copper foil layer 102, and the second dry film layer 107 is disposed on the second inner copper foil layer 103. Then, the first dry film layer 106 and the second dry film layer 107 are exposed and developed, so that a plurality of first through holes 1061 are formed in the first dry film layer 106, and a second through hole 1071 is formed in the second dry film layer 107. The plurality of first through holes 1061 are disposed at intervals, and a portion of the first inner copper foil layer 102 is exposed at the bottom of each of the first through holes 1061. The second through hole 1071 is connected to the opening 105, and a portion of the first inner copper foil layer 102 is exposed at the bottom of the opening 105 and the second through hole 1071.

[0091] S13: See Figure 2 , electroplating is performed in the second through hole 1071 and the opening 105 to form a first conductive body 108, and the first conductive body 108 electrically connects the first inner copper foil layer 102 and the second inner copper foil layer 103. Electroplating is performed in the first through hole 1061 to form a plurality of thermal conductive pillars 14, and one end of the thermal conductive pillars 14 is connected to the first inner copper foil layer 102.

[0092] S14: See Figure 3 and Figure 4 , remove the first dry film layer 106 and the second dry film layer 107 , and etch the first inner copper foil layer 102 to obtain the first inner circuit layer 11 , and etch the second inner copper foil layer 103 to obtain the second inner circuit layer 12 .

[0093] The copper clad substrate 101 is divided into a first area A, a second area B and a connection area C. The connection area C is located between the first area A and the second area B. The thermally conductive column 14 and the first conductive body 108 are disposed in the first area A. The first area A is used to accommodate the heating element 70 .

[0094] In this embodiment, step S1 further includes the steps of:

[0095] S15: See Figure 5 A covering layer 109 is disposed in the connection area C. The covering layer 109 is disposed on the outer sides of the first inner circuit layer 11 and the second inner circuit layer 12. A glue layer 110 is also disposed between the covering layer 109 and the first inner circuit layer 11 or the second inner circuit layer 12.

[0096] S16: a peelable layer 111 is disposed on the cover layer 109, and the material of the peelable layer 111 can be release adhesive.

[0097] S17: See Figure 6 , the thermal conductive agent 15 is filled between two adjacent thermal conductive pillars 14 to obtain the circuit substrate 10 .

[0098] S2: See Figure 7 and Figure 8 , provide a first copper foil layer 20, a second copper foil layer 30, a first adhesive layer 40 and a second adhesive layer 50, so that the first adhesive layer 40 is arranged between the first copper foil layer 20 and the first inner circuit layer 11, and the second adhesive layer 50 is arranged between the second copper foil layer 30 and the second inner circuit layer 12. The first adhesive layer 40 is provided with an opening 41, and the thermal conductive column 14 passes through the opening 41. The second adhesive layer 50 is arranged between the second copper foil layer 30 and the second inner circuit layer 12. Then, the first copper foil layer 20, the first adhesive layer 40, the circuit substrate 10, the second adhesive layer 50 and the second copper foil layer 30 are pressed together to obtain an intermediate 200 (see Figure 8 ).

[0099] The first copper foil layer 20 seals the liquid storage space 141 , and the depth D of the thermal conductor 15 is lower than the height H of the thermal conductive column 14 , so that a cavity 142 exists between the first copper foil layer 20 and the thermal conductor 15 .

[0100] In this embodiment, in step S2, see Figure 7 The first copper foil layer 20 includes a main body 21 and a plurality of connecting parts 22 disposed on the main body 21. After lamination, the connecting parts 22 are connected to the thermally conductive pillars 14. The connecting parts 22 may be made of a metal adhesive, thereby enhancing the connection strength between the first copper foil layer 20 and the thermally conductive pillars 14 and sealing the gap between the first copper foil layer 20 and the thermally conductive pillars 14.

[0101] S3: See Fig. 9 , the two opposite surfaces of the intermediate body 200 are respectively electroplated to form a first electroplating layer 23 and a second electroplating layer 31, the first electroplating layer 23 is arranged on the first copper foil layer 20, and the second electroplating layer 31 is arranged on the second copper foil layer 30, and then the first copper foil layer 20 and the first electroplating layer 23 are etched to obtain a first outer circuit layer 24, and the second copper foil layer 30 and the second electroplating layer 31 are etched to obtain a second outer circuit layer 32.

[0102] In this embodiment, step S3 further includes:

[0103] S30: Fig. 9As shown, a first groove 61, a second groove 62 and a third through hole 63 are provided on the intermediate body 200, the first groove 61 penetrates the first copper foil layer 20 and the first adhesive layer 40, and the first inner circuit layer 11 is exposed at the bottom of the first groove 61. The second groove 62 penetrates the second copper foil layer 30 and the second adhesive layer 50. The third through hole 63 penetrates the first copper foil layer 20, the first adhesive layer 40, the circuit substrate 10, the second adhesive layer 50 and the second copper foil layer 30.

[0104] After electroplating, part of the first electroplating layer 23 is filled into the first groove 61 to form a second conductive body 611, and the second conductive body 611 is electrically connected to the first copper foil layer 20 and the first inner circuit layer 11. Part of the second electroplating layer 31 is filled into the second groove 62 to form a third conductive body 621, and the third conductive body 621 is electrically connected to the second copper foil layer 30 and the second inner circuit layer 12. Part of the first electroplating layer 23 or the second electroplating layer 31 is attached to the inner wall of the third through hole 63 to form a hollow fourth conductive body 631.

[0105] In this embodiment, step S3 also includes:

[0106] S31: See Fig.10 A solder mask 64 is disposed on the first outer circuit layer 24 and the second outer circuit layer 32 , and a portion of the solder mask 64 is filled into the hollow fourth conductive body 631 .

[0107] S4: See Fig.11 A first groove 60 is provided in the intermediate body 200 . Along the thickness direction F of the intermediate body 200 , the first groove 60 corresponds to the plurality of thermal conductive pillars 14 . The first groove 60 penetrates the second outer circuit layer 32 , the second adhesive layer 50 , the second inner circuit layer 12 and the substrate layer 13 . The first inner circuit layer 11 is exposed at the bottom of the first groove 60 .

[0108] In this embodiment, step S4 further includes the steps of:

[0109] The intermediate body 200 is provided with a second slot 65 and a third slot 66, the second slot 65 and the third slot 66 correspond to the connection area C, and the second slot 65 is arranged opposite to the third slot 66. The second slot 65 penetrates one of the solder mask layers 64, the first outer circuit layer 24 and a portion of the first adhesive layer 40, and one of the peelable layers 111 is exposed at the bottom of the second slot 65. The third slot 66 penetrates another of the solder mask layers 64, the second outer circuit layer 32 and a portion of the second adhesive layer 50, and another of the peelable layers 111 is exposed at the bottom of the third slot 66. Furthermore, the two peelable layers 111 are peeled off, so that the cover layer 109 is exposed at the bottom of the second slot 65 or the third slot 66, thereby forming a soft board part.

[0110] S5: See Fig.12 , a heating element 70 is disposed at the bottom of the first slot 60 to obtain the circuit board 100 .

[0111] In this embodiment, step S5 further includes: disposing a metal layer 601 at the bottom of the first slot 60 , wherein the metal layer 601 is made of nickel-palladium-gold and is used to enhance the thermal conductivity between the heating element 70 and the second inner circuit layer 12 .

[0112] In this embodiment, step S5 further includes: electrically connecting the heating element 70 and the second outer circuit layer 32 , wherein the electrical connection includes connecting the heating element 70 and the second outer circuit layer 32 using a metal wire 71 .

[0113] See also Fig.12 The embodiment of the present invention provides a circuit board 100, which can be used in a camera module. The circuit board 100 includes a circuit substrate 10, a first outer circuit layer 24, a second outer circuit layer 32, a first adhesive layer 40, a second adhesive layer 50 and a heating element 70. The circuit substrate 10 is disposed between the first outer circuit layer 24 and the second outer circuit layer 32, the first adhesive layer 40 is disposed between the first outer circuit layer 24 and the circuit substrate 10, and the second adhesive layer 50 is disposed between the second outer circuit layer 32 and the circuit substrate 10. The heating element 70 is embedded in the circuit board 100.

[0114] The circuit substrate 10 includes a first inner circuit layer 11 , a second inner circuit layer 12 , a base material layer 13 , a plurality of heat-conducting pillars 14 , and a heat-conducting agent 15 .

[0115] The first outer circuit layer 24 is disposed on the outer side of the first inner circuit layer 11, the second outer circuit layer 32 is disposed on the outer side of the second inner circuit layer 12, the thermally conductive pillars 14 are disposed between the first outer circuit layer 24 and the first inner circuit layer 11, a liquid storage space 141 is formed between two adjacent thermally conductive pillars 14, and the thermally conductive agent 15 is filled in the liquid storage space 141. The depth D of the thermally conductive agent 15 is lower than the height H of the thermally conductive pillars 14, so that a cavity 142 exists between the first outer circuit layer 24 and the thermally conductive agent 15.

[0116] The circuit board 100 is provided with a first slot 60. Along the thickness direction F of the circuit board 100, the first slot 60 corresponds to the plurality of heat-conducting pillars 14. The first slot 60 penetrates the first outer circuit layer 24, the first adhesive layer 40, the first inner circuit layer 11 and the substrate layer 13. The second inner circuit layer 12 is exposed at the bottom of the first slot 60. The heating element 70 is disposed at the bottom of the first slot 60.

[0117] During specific operation, the heat generated by the heating element 70 is conducted to the heat-conducting column 14 via the first inner circuit layer 11, and the heat-conducting column 14 conducts the heat to the thermal conductive agent 15 (i.e., heat conduction). The thermal conductive agent 15 absorbs the heat and undergoes a phase change to be converted into heat-conducting steam, and the heat-conducting steam carries the heat into the cavity 142, and then condenses in the cavity 142 and turns back into the heat-conducting agent 15, and then the heat-conducting agent 15 flows back into the liquid storage space 141 (i.e., heat convection). The circuit board 100 provided in the present application can conduct the heat generated by the heating element 70 to the thermal conductive agent 15 by providing the heat-conducting column 14 and the thermal conductive agent 15, and form heat convection through the thermal conductive agent 15 and the cavity 142, thereby accelerating the heat dissipation efficiency.

[0118] In this embodiment, the circuit board 100 also includes a plurality of connecting parts 22, and the connecting parts 22 are arranged between the first outer circuit layer 24 and the thermally conductive column 14. The material of the connecting parts 22 is a metal adhesive. The connecting parts 22 can seal the gap between the first outer circuit layer 24 and the thermally conductive column 14, thereby preventing heat-conducting steam from escaping from the cavity 142.

[0119] In this embodiment, the heat conducting agent 15 is at least one of heat conducting oil, ammonia water and water.

[0120] The above description is only an optimized specific implementation of the present application, but it cannot be limited to this implementation in the actual application process. For ordinary technicians in this field, other variations and changes made according to the technical concept of the present application should all fall within the protection scope of the present application.

Claims

1. A method for manufacturing a circuit board, characterized in that: Includes steps: A circuit substrate is provided, the circuit substrate comprising a first inner circuit layer, a second inner circuit layer, a base material layer, a plurality of heat-conducting columns and a heat-conducting agent, the base material layer is arranged between the first inner circuit layer and the second inner circuit layer, the heat-conducting columns are arranged on the first inner circuit layer at a distance, a liquid storage space is provided between two adjacent heat-conducting columns, and the heat-conducting agent is filled in the liquid storage space; A first outer circuit layer is arranged on the heat-conducting column, and a second outer circuit layer is arranged on the second inner circuit layer to obtain an intermediate body, wherein the first outer circuit layer encloses the liquid storage space, and a cavity exists between the first outer circuit layer and the heat-conducting agent; A first slot is provided in the intermediate body, and along the thickness direction of the intermediate body, the first slot corresponds to the plurality of thermal conductive pillars, the first slot penetrates the second outer circuit layer, the second inner circuit layer and the substrate layer, and the first inner circuit layer is exposed at the bottom of the first slot; Disposing a metal layer in the first groove; The heating element is installed in the first slot, and the heating element is installed on the metal layer to obtain the circuit board.

2. The manufacturing method according to claim 1, characterized in that The manufacturing method of the circuit substrate comprises: A copper-clad substrate is provided, the copper-clad substrate comprising a first inner copper foil layer, a second inner copper foil layer and the base material layer, wherein the base material layer is disposed between the first inner copper foil layer and the second inner copper foil layer; A dry film layer is disposed on the first inner copper foil layer, wherein the dry film layer has a plurality of through holes distributed at intervals. Electroplating in the through hole to form a plurality of the thermally conductive pillars; removing the dry film layer; and The first inner copper foil layer is etched to obtain the first inner circuit layer, and the second inner copper foil layer is etched to obtain the second inner circuit layer, thereby obtaining the circuit substrate.

3. The manufacturing method according to claim 2, characterized in that: The method for manufacturing the circuit substrate further includes: Disposing a covering layer on the first inner circuit layer and the second inner circuit layer; After obtaining the intermediate, the manufacturing method further comprises the steps of: A second slot and a third slot are disposed on two opposite sides of the intermediate body, and the cover layer is exposed at the bottom of the second slot and the third slot.

4. The manufacturing method according to claim 2, characterized in that: The step of "arranging a first outer circuit layer on the thermally conductive column" includes: Laminating a first outer copper foil layer on the heat-conducting column; Electroplating on the first outer copper foil layer to form a first electroplating layer; The first outer copper foil layer and the first electroplating layer are etched to form the first outer circuit layer.

5. The manufacturing method according to claim 2, characterized in that: The step of "arranging a second outer circuit layer on the second inner circuit layer" includes: Laminating a second outer copper foil layer on the second inner circuit layer; Electroplating on the second outer copper foil layer to form a second electroplating layer; The second outer copper foil layer and the second electroplating layer are etched to form the second outer circuit layer.

6. The manufacturing method according to claim 4, characterized in that: The first outer copper foil layer includes a main body portion and a connecting portion, and the connecting portion is disposed between the main body portion and the heat conducting column.

7. The manufacturing method according to claim 1, characterized in that: The heat conducting agent is at least one of heat conducting oil, ammonia water and water.

8. A circuit board, characterized in that: It includes a circuit substrate, a first outer circuit layer, a second outer circuit layer, a heating element and a metal layer, wherein the circuit substrate is arranged between the first outer circuit layer and the second outer circuit layer; The circuit substrate comprises a first inner circuit layer, a second inner circuit layer, a base material layer, a plurality of heat-conducting columns and a heat-conducting agent, wherein the base material layer is arranged between the first inner circuit layer and the second inner circuit layer, the heat-conducting columns are arranged on the first inner circuit layer at intervals, a liquid storage space is provided between two adjacent heat-conducting columns, and the heat-conducting agent is filled in the liquid storage space; The first outer circuit layer is arranged on the heat-conducting column to close the liquid storage space, a cavity exists between the first outer circuit layer and the heat-conducting agent, and the second outer circuit layer is arranged outside the second inner circuit layer; The circuit board is provided with a slot, and along the thickness direction of the circuit board, the slot corresponds to the plurality of heat-conducting pillars, the slot passes through the second outer circuit layer, the second inner circuit layer and the substrate layer, the first inner circuit layer is exposed at the bottom of the slot, and the heating element is installed at the bottom of the slot; The metal layer is arranged at the bottom of the slot, and the heating element is installed on the metal layer.

9. The circuit board according to claim 8, characterized in that: The heat conducting agent is at least one of heat conducting oil, ammonia water and water.

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