Circuit board connecting structure and manufacturing method thereof

Abstract

The application provides a manufacturing method of a circuit board connecting structure, comprising the following steps: providing a first circuit board, wherein the first circuit board comprises at least one first conductive circuit layer; providing a second circuit board, wherein the second circuit board comprises at least one second conductive circuit layer; connecting the first circuit board and the second circuit board through a colloid to obtain an intermediate body; setting a first blind hole in the intermediate body; and forming a first conductive part in the first blind hole and electrically connecting the first conductive part with the first conductive circuit layer and the second conductive circuit layer, so as to obtain the circuit board connecting structure. The application avoids opening a cover at the connecting position of the first circuit board and the second circuit board, and makes the connecting position of the first circuit board and the second circuit board have a smaller thickness. The application also provides a circuit board connecting structure prepared by the method.

Description

TECHNICAL FIELD

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

[0002] In recent years, various electronic products develop towards multi-function, integration and miniaturization. For this reason, two or more circuit boards of different types or materials are usually electrically connected together. The connection between the two circuit boards usually has a thickness limit, so that the cover opening and thickness reduction are usually required at the connection overlap of the two circuit boards. However, some circuit boards are not suitable for cover opening, or special equipment is required for cover opening in the circuit board. SUMMARY

[0003] Therefore, the present application provides a manufacturing method of a circuit board connecting structure with a small thickness at the connection between two circuit boards.

[0004] In addition, the present application also provides a circuit board connecting structure manufactured by the above manufacturing method.

[0005] An embodiment of the present application provides a manufacturing method of a circuit board connecting structure, comprising the following steps:

[0006] A first circuit board is provided, which comprises a first base layer, a first protective layer and at least one first conductive circuit layer between the first base layer and the first protective layer;

[0007] A second circuit board is provided, which comprises a second base layer, a second protective layer and at least one second conductive circuit layer between the second base layer and the second protective layer;

[0008] One side of the first circuit board and one side of the second circuit board are connected by a colloid, so that the first circuit board and the second circuit board are connected to obtain an intermediate body;

[0009] A first blind hole is formed in the intermediate body; and

[0010] A first conductive part is formed in the first blind hole, and the first conductive part electrically connects the first conductive circuit layer and the second conductive circuit layer, so that the first circuit board and the second circuit board are electrically connected, thereby obtaining the circuit board connecting structure.

[0011] An embodiment of the present application also provides a circuit board connecting structure, comprising:

[0012] A first circuit board, which comprises a first base layer, a first protective layer and at least one first conductive circuit layer between the first base layer and the first protective layer;

[0013] a second circuit board comprising a second base layer, a second protective layer, and at least a second conductive circuit layer between the second base layer and the second protective layer; and

[0014] a colloid between the first circuit board and the second circuit board, the colloid being used to connect one side of the first circuit board and one side of the second circuit board;

[0015] wherein the circuit board connecting structure is provided with a first conductive member, the first conductive member being used to electrically connect the first conductive circuit layer and the second conductive circuit layer, so as to electrically connect the first circuit board and the second circuit board.

[0016] The present application connects the first circuit board and the second circuit board through the colloid to obtain the intermediate body, and forms a first conductive member in the intermediate body to realize the electrical connection between the first circuit board and the second circuit board. The present application avoids opening the cover at the connection part of the first circuit board and the second circuit board, and makes the connection part of the first circuit board and the second circuit board have a smaller thickness. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a structural schematic diagram of a first circuit board and a second circuit board provided in an embodiment of the present application.

[0018] Figure 2 is a structural schematic diagram of a first circuit board and a second circuit board provided in an embodiment of the present application. Figure 1 is a structural schematic diagram of the first circuit board and the second circuit board after being connected through a colloid, a first cover film and a second cover film.

[0019] Figure 3 is a structural schematic diagram of an intermediate body provided in an embodiment of the present application. Figure 2 is a structural schematic diagram of the intermediate body after a first blind hole and a second blind hole are formed in the intermediate body.

[0020] Figure 4 is a structural schematic diagram of a circuit board connecting structure obtained after a first conductive member and a second conductive member are respectively formed in the first blind hole and the second blind hole. Figure 3 is a structural schematic diagram of a circuit board connecting structure obtained after a first conductive member and a second conductive member are respectively formed in the first blind hole and the second blind hole.

[0021] MAIN ELEMENT SYMBOL EXPLANATION

[0022] circuit board connecting structure 100

[0023] first circuit board 10

[0024] first base layer 101

[0025] first protective layer 102

[0026] first conductive circuit layer 103

[0027] First solder pad 1031

[0028] First insulating layer 104

[0029] Third protective layer 105

[0030] Third conductive circuit layer 106

[0031] Third solder pad 1061

[0032] Third insulating layer 107

[0033] First conductive part 11

[0034] Second conductive part 12

[0035] Third conductive part 13

[0036] Second circuit board 20

[0037] Second base layer 201

[0038] Second protective layer 202

[0039] Second conductive circuit layer 203

[0040] Second solder pad 2031

[0041] Second insulating layer 204

[0042] Fourth protective layer 205

[0043] Fourth conductive circuit layer 206

[0044] Fourth solder pad 2061

[0045] Fourth insulating layer 207

[0046] Fourth conductive part 21

[0047] Fifth conductive part 22

[0048] Sixth conductive part 23

[0049] Colloid 30

[0050] First cover film 31

[0051] Second cover film 32

[0052] Intermediate body 40

[0053] First blind hole 41

[0054] Second blind hole 42

[0055] First conductive member 50

[0056] Second conductive member 51

[0057] The following detailed description will further explain the present application with reference to the above mentioned drawings. DETAILED DESCRIPTION

[0058] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to 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 the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0059] 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 herein is for describing particular embodiments only and is not intended to be limiting of the application.

[0060] In order to further clarify the technical means and effects taken by the present application to achieve the predetermined purpose, the following will be described in detail in combination with the drawings and the preferred embodiments.

[0061] An embodiment of the present application provides a manufacturing method of a circuit board connecting structure, comprising the following steps:

[0062] Step S11, please refer to Figure 1 , providing a first circuit board 10.

[0063] In an embodiment, the first circuit board 10 comprises a first base layer 101, a first protective layer 102 located on one side of the first base layer 101, at least one first conductive circuit layer 103 located between the first base layer 101 and the first protective layer 102, and a first insulating layer 104 located between two adjacent first conductive circuit layers 103. In another embodiment, the first circuit board 10 further comprises a third protective layer 105 located on the other side of the first base layer 101, at least one third conductive circuit layer 106 located between the first base layer 101 and the third protective layer 105, and a third insulating layer 107 located between two adjacent third conductive circuit layers 106. In this embodiment, the number of the first conductive circuit layer 103 and the third conductive circuit layer 106 is three. In other embodiments, the number of the first conductive circuit layer 103 and the third conductive circuit layer 106 can be set as needed.

[0064] The material of the first base layer 101, the first insulating layer 104 and the third insulating layer 107 can be selected from one of the following resins: epoxy resin, polypropylene (PP), BT resin, polyphenylene oxide (PPO), polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), etc. In this embodiment, the material of the first base layer 101 is epoxy resin, and the materials of the first insulating layer 104 and the third insulating layer 107 are polyimide.

[0065] In an embodiment, the first conductive circuit layer 103 includes a first solder pad 1031, and the first solder pad 1031 is located at one end of the first conductive circuit layer 103. The thickness of the first solder pad 1031 in the first conductive circuit layer 103 is greater than that of other positions in the first conductive circuit layer 103, so as to increase the contact area of the connection between the first circuit board 10 and the second circuit board 20, thereby improving the reliability of the connection between the first circuit board 10 and the second circuit board 20.

[0066] In an embodiment, the third conductive circuit layer 106 includes a third solder pad 1061, and the third solder pad 1061 is located at one end of the third conductive circuit layer 106. The thickness of the third solder pad 1061 in the third conductive circuit layer 106 is greater than that of other positions in the third conductive circuit layer 106, so as to increase the contact area of the connection between the first circuit board 10 and the second circuit board 20, thereby improving the reliability of the connection between the first circuit board 10 and the second circuit board 20.

[0067] In this embodiment, the first protective layer 102 and the third protective layer 105 are both cover films.

[0068] In this embodiment, the first circuit board 10 is provided with a plurality of first conductive parts 11, second conductive parts 12 and a plurality of third conductive parts 13. The first conductive part 11 is used to electrically connect two adjacent first conductive circuit layers 103, the second conductive part 12 is used to electrically connect the first conductive circuit layer 103 arranged adjacent to the first base layer 101 and the third conductive circuit layer 106 arranged adjacent to the first base layer 101, and the third conductive part 13 is used to electrically connect two adjacent third conductive circuit layers 106.

[0069] Step S12, providing a second circuit board 20.

[0070] In an embodiment, the second circuit board 20 comprises a second base layer 201, a second protective layer 202 located on one side of the second base layer 201, at least one second conductive circuit layer 203 located between the second base layer 201 and the second protective layer 202, and a second insulating layer 204 located between two adjacent second conductive circuit layers 203. In another embodiment, the second circuit board 20 further comprises a fourth protective layer 205 located on the other side of the second base layer 201, at least one fourth conductive circuit layer 206 located between the second base layer 201 and the fourth protective layer 205, and a fourth insulating layer 207 located between two adjacent fourth conductive circuit layers 206. In this embodiment, the number of second conductive circuit layers 203 and fourth conductive circuit layers 206 is three. In other embodiments, the number of second conductive circuit layers 203 and fourth conductive circuit layers 206 can be set as needed.

[0071] In an embodiment, the material of the second base layer 201 can be the same as that of the first base layer 101, and the materials of the second insulating layer 204 and the fourth insulating layer 207 can be the same as that of the first insulating layer 104. For details, please refer to the material of the first base layer 101 and the material of the first insulating layer 104, which will not be described here.

[0072] In an embodiment, the second conductive circuit layer 203 comprises a second solder pad 2031, and the second solder pad 2031 is located at one end of the second conductive circuit layer 203. Compared with the thickness of other positions in the second conductive circuit layer 203, the thickness of the second solder pad 2031 in the second conductive circuit layer 203 is larger, so as to increase the contact area of the connection between the first circuit board 10 and the second circuit board 20, thereby improving the reliability of the connection between the first circuit board 10 and the second circuit board 20.

[0073] In an embodiment, the fourth conductive circuit layer 206 comprises a fourth solder pad 2061, and the fourth solder pad 2061 is located at one end of the fourth conductive circuit layer 206. Compared with the thickness of other positions in the fourth conductive circuit layer 206, the thickness of the fourth solder pad 2061 in the fourth conductive circuit layer 206 is larger, so as to increase the contact area of the connection between the first circuit board 10 and the second circuit board 20, thereby improving the reliability of the connection between the first circuit board 10 and the second circuit board 20.

[0074] In this embodiment, the second protective layer 202 and the fourth protective layer 205 are both cover films.

[0075] In the embodiment, the second circuit board 20 is provided with a plurality of fourth conductive parts 21, a fifth conductive part 22 and a plurality of sixth conductive parts 23. The fourth conductive part 21 is used for electrically connecting two adjacent second conductive circuit layers 203, the fifth conductive part 22 is used for electrically connecting the second conductive circuit layer 203 arranged adjacent to the second base layer 201 and the fourth conductive circuit layer 206 arranged adjacent to the second base layer 201, and the sixth conductive part 23 is used for electrically connecting two adjacent fourth conductive circuit layers 206.

[0076] Step S13, please refer to Figure 2 The one side of the first circuit board 10 and the one side of the second circuit board 20 are connected by the adhesive 30, so that the first circuit board 10 and the second circuit board 20 are connected to obtain an intermediate body 40.

[0077] In other embodiments, after the one side of the first circuit board 10 and the one side of the second circuit board 20 are connected by the adhesive 30, a first cover film 31 can be formed on one surface of the adhesive 30, and the first cover film 31 is flush with the surface of the first base layer 101 and the surface of the first protective layer 102 away from the first base layer 101, and the surface of the second protective layer 202 away from the second base layer 201. A second cover film 32 is formed on the other surface of the adhesive 30, and the second cover film 32 is flush with the surface of the second base layer 201 and the surface of the third protective layer 105 away from the first base layer 101, and the surface of the fourth protective layer 205 away from the second base layer 201.

[0078] Step S14, please refer to Figure 3 A first blind hole 41 is formed in the intermediate body 40.

[0079] Specifically, the first blind hole 41 can be formed in the intermediate body 40 by laser depth ablation.

[0080] The first blind hole 41 penetrates the first cover film 31, the first solder pad 1031 and the second solder pad 2031, and the bottom of the first blind hole 41 corresponds to the first insulating layer 104, the adhesive 30 and the second insulating layer 204.

[0081] In other embodiments, after the first blind hole 41 is formed in the intermediate body 40, a second blind hole 42 can also be formed in the intermediate body 40. The second blind hole 42 penetrates the second cover film 32, the third pad 1061 and the fourth pad 2061, and the bottom of the second blind hole 42 corresponds to the third insulating layer 107, the adhesive 30 and the fourth insulating layer 207. In an embodiment, the second blind hole 42 can also be formed by laser depth ablation.

[0082] At step S15, referring to Figure 4 A first conductive member 50 is formed in the first blind hole 41, and the first conductive member 50 is electrically connected to the first conductive circuit layer 103 and the second conductive circuit layer 203, so that the first circuit board 10 and the second circuit board 20 are electrically connected, thereby obtaining the circuit board connection structure 100.

[0083] Specifically, the first conductive member 50 can be formed by electroplating metal or filling conductive material in the first blind hole 41. The electroplated metal can be copper, nickel or gold. The filled conductive material can be conductive paste, such as copper paste, tin paste and silver paste.

[0084] The first conductive member 50 is used to electrically connect the first pad 1031 and the second pad 2031, so that the first conductive circuit layer 103 and the second conductive circuit layer 203 are electrically connected.

[0085] In other embodiments, after the first conductive member 50 is formed, a second conductive member 51 can also be formed in the second blind hole 42, and the second conductive member 51 is electrically connected to the third conductive circuit layer 106 and the fourth conductive circuit layer 206, thereby obtaining the circuit board connection structure 100.

[0086] The second conductive member 51 is used to electrically connect the third pad 1061 and the fourth pad 2061, so that the third conductive circuit layer 106 and the fourth conductive circuit layer 206 are electrically connected.

[0087] At step S15, referring to Figure 4 An embodiment of the present application also provides a circuit board connection structure 100, which comprises a first circuit board 10, a second circuit board 20, an adhesive 30, a first cover film 31 and a second cover film 32.

[0088] In an embodiment, the first circuit board 10 comprises a first base layer 101, a first protective layer 102 on one side of the first base layer 101, at least one first conductive circuit layer 103 between the first base layer 101 and the first protective layer 102, and a first insulating layer 104 between two adjacent first conductive circuit layers 103. In another embodiment, the first circuit board 10 further comprises a third protective layer 105 on the other side of the first base layer 101, at least one third conductive circuit layer 106 between the first base layer 101 and the third protective layer 105, and a third insulating layer 107 between two adjacent third conductive circuit layers 106. In this embodiment, the number of the first conductive circuit layers 103 and the third conductive circuit layers 106 is three. In other embodiments, the number of the first conductive circuit layers 103 and the third conductive circuit layers 106 can be set as needed.

[0089] The material of the first base layer 101, the first insulating layer 104, and the third insulating layer 107 can be selected from one of the following resins: epoxy resin, polypropylene (PP), BT resin, polyphenylene oxide (PPO), polyimide (PI), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN). In this embodiment, the material of the first base layer 101 is epoxy resin, and the materials of the first insulating layer 104 and the third insulating layer 107 are polyimide.

[0090] In an embodiment, the first conductive circuit layer 103 comprises a first solder pad 1031, and the first solder pad 1031 is located at one end of the first conductive circuit layer 103. Compared with the thickness of other positions in the first conductive circuit layer 103, the thickness of the first solder pad 1031 in the first conductive circuit layer 103 is larger, so as to increase the contact area of the connection between the first circuit board 10 and the second circuit board 20, thereby improving the reliability of the connection between the first circuit board 10 and the second circuit board 20.

[0091] In an embodiment, the third conductive circuit layer 106 includes a third solder pad 1061, and the third solder pad 1061 is located at one end of the third conductive circuit layer 106. In this embodiment, the thickness of the third solder pad 1061 is greater than the thickness of other positions in the third conductive circuit layer 106, so as to increase the contact area of the connection between the first circuit board 10 and the second circuit board 20, thereby improving the reliability of the connection between the first circuit board 10 and the second circuit board 20.

[0092] In this embodiment, the first protective layer 102 and the third protective layer 105 are both cover films.

[0093] In this embodiment, the first circuit board 10 includes a plurality of first conductive parts 11, a second conductive part 12, and a plurality of third conductive parts 13. The first conductive part 11 is used to electrically connect two adjacent first conductive circuit layers 103, the second conductive part 12 is used to electrically connect the first conductive circuit layer 103 arranged adjacent to the first base layer 101 and the third conductive circuit layer 106 arranged adjacent to the first base layer 101, and the third conductive part 13 is used to electrically connect two adjacent third conductive circuit layers 106.

[0094] In an embodiment, the second circuit board 20 includes a second base layer 201, a second protective layer 202 located on one side of the second base layer 201, at least one second conductive circuit layer 203 located between the second base layer 201 and the second protective layer 202, and a second insulating layer 204 located between two adjacent second conductive circuit layers 203. In another embodiment, the second circuit board 20 further includes a fourth protective layer 205 located on the other side of the second base layer 201, at least one fourth conductive circuit layer 206 located between the second base layer 201 and the fourth protective layer 205, and a fourth insulating layer 207 located between two adjacent fourth conductive circuit layers 206. In this embodiment, the number of the second conductive circuit layer 203 and the fourth conductive circuit layer 206 is three. In other embodiments, the number of the second conductive circuit layer 203 and the fourth conductive circuit layer 206 can be set as needed.

[0095] In an embodiment, the material of the second base layer 201 can be the same as the material of the first base layer 101, and the materials of the second insulating layer 204 and the fourth insulating layer 207 can be the same as the material of the first insulating layer 104. For details, please refer to the material of the first base layer 101 and the material of the first insulating layer 104, which will not be described here.

[0096] In an embodiment, the second conductive circuit layer 203 comprises a second solder pad 2031, and the second solder pad 2031 is located at one end of the second conductive circuit layer 203. The thickness of the second solder pad 2031 in the second conductive circuit layer 203 is greater than the thickness of other positions in the second conductive circuit layer 203, so as to increase the contact area of the connection between the first circuit board 10 and the second circuit board 20, thereby improving the reliability of the connection between the first circuit board 10 and the second circuit board 20.

[0097] In an embodiment, the fourth conductive circuit layer 206 comprises a fourth solder pad 2061, and the fourth solder pad 2061 is located at one end of the fourth conductive circuit layer 206. The thickness of the fourth solder pad 2061 in the fourth conductive circuit layer 206 is greater than the thickness of other positions in the fourth conductive circuit layer 206, so as to increase the contact area of the connection between the first circuit board 10 and the second circuit board 20, thereby improving the reliability of the connection between the first circuit board 10 and the second circuit board 20.

[0098] In the embodiment, the second protective layer 202 and the fourth protective layer 205 are both cover films.

[0099] In the embodiment, the second circuit board 20 comprises a plurality of fourth conductive parts 21, a fifth conductive part 22, and a plurality of sixth conductive parts 23. The fourth conductive part 21 is used to electrically connect two adjacent second conductive circuit layers 203, the fifth conductive part 22 is used to electrically connect the second conductive circuit layer 203 arranged adjacent to the second base layer 201 and the fourth conductive circuit layer 206 arranged adjacent to the second base layer 201, and the sixth conductive part 23 is used to electrically connect two adjacent fourth conductive circuit layers 206.

[0100] The adhesive 30 is located between the first circuit board 10 and the second circuit board 20. The adhesive 30 is used to connect one side surface of the first circuit board 10 and one side surface of the second circuit board 20.

[0101] The first cover film 31 is located on one surface of the adhesive 30. The surface of the first cover film 31 away from the first base layer 101 and the surface of the first protective layer 102 away from the first base layer 101 are flush with the surface of the second protective layer 202 away from the second base layer 201.

[0102] The second cover film 32 is located on the other surface of the colloid 30. The surface of the second base layer 201 away from the second cover film 32 and the surface of the third protective layer 105 away from the first base layer 101 are flush with the surface of the fourth protective layer 205 away from the second base layer 201.

[0103] The circuit board connecting structure 100 is provided with a first conductive piece 50. The first conductive piece 50 penetrates the first cover film 31, the first solder pad 1031 and the second solder pad 2031, and the bottom of the first conductive piece 50 corresponds to the first insulating layer 104, the colloid 30 and the second insulating layer 204. The first conductive piece 50 is used to electrically connect the first solder pad 1031 and the second solder pad 2031, so as to electrically connect the first conductive circuit layer 103 and the second conductive circuit layer 203, and electrically connect the first circuit board 10 and the second circuit board 20. In an embodiment, the material of the first conductive piece 50 is metal or conductive paste, wherein the metal can be copper, nickel or gold. The conductive paste can be copper paste, tin paste and silver paste, etc.

[0104] In other embodiments, the circuit board connecting structure 100 is also provided with a second conductive piece 51. The second conductive piece 51 penetrates the second cover film 32, the third solder pad 1061 and the fourth solder pad 2061, and the bottom of the second conductive piece 51 corresponds to the third insulating layer 107, the colloid 30 and the fourth insulating layer 207. The second conductive piece 51 is used to electrically connect the third solder pad 1061 and the fourth solder pad 2061, so as to electrically connect the third conductive circuit layer 106 and the fourth conductive circuit layer 206, and electrically connect the first circuit board 10 and the second circuit board 20. In an embodiment, the material of the second conductive piece 51 is metal or conductive paste, wherein the metal can be copper, nickel or gold. The conductive paste can be copper paste, tin paste and silver paste, etc.

[0105] The present application connects the first circuit board 10 and the second circuit board 20 through the colloid 30 to obtain the intermediate body 40, and forms a first conductive piece 50 in the intermediate body 40 to realize the electrical connection between the first circuit board 10 and the second circuit board 20. The present application avoids opening the cover at the connection of the first circuit board 10 and the second circuit board 20, and makes the connection of the first circuit board 10 and the second circuit board 20 have a smaller thickness.

[0106] The above description is only one optimized specific embodiment of the present application, but in actual application process, it cannot be limited to this embodiment.

Claims

1. A method for manufacturing a circuit board connection structure, characterized in that, Includes the following steps: A first circuit board is provided, the first circuit board including a first base layer, a first protective layer and at least one first conductive line layer located between the first base layer and the first protective layer; A second circuit board is provided, the second circuit board including a second base layer, a second protective layer, and at least one second conductive line layer located between the second base layer and the second protective layer; One side of the first circuit board and one side of the second circuit board are connected by an adhesive to connect the first circuit board and the second circuit board, thereby obtaining an intermediate body; A first covering film is formed on one surface of the colloid; A first blind hole is formed in the intermediate body, and the first blind hole penetrates the first covering film; as well as A first conductive element is formed in the first blind via, and the first conductive element is electrically connected to the first conductive circuit layer and the second conductive circuit layer, so that the first circuit board and the second circuit board are electrically connected, thereby obtaining the circuit board connection structure.

2. The method for manufacturing the circuit board connection structure as described in claim 1, characterized in that, The first conductive line layer includes a first solder pad, and the first solder pad is located at one end of the first conductive line layer. The second conductive line layer includes a second solder pad, and the second solder pad is located at one end of the second conductive line layer. The first conductive element is used to electrically connect the first solder pad and the second solder pad.

3. The method for manufacturing the circuit board connection structure as described in claim 1, characterized in that, The surface of the first covering film away from the first base layer, the surface of the first protective layer away from the first base layer, and the surface of the second protective layer away from the second base layer are all flush.

4. The method for manufacturing the circuit board connection structure as described in claim 1, characterized in that, The first circuit board further includes a third protective layer and at least one third conductive layer. The third protective layer is located on the side of the first base layer away from the first protective layer, and the third conductive layer is located between the first base layer and the third protective layer. The second circuit board further includes a fourth protective layer and at least one fourth conductive layer. The fourth protective layer is located on the side of the second base layer away from the second protective layer, and the fourth conductive layer is located between the second base layer and the fourth protective layer.

5. The method for manufacturing the circuit board connection structure as described in claim 4, characterized in that, Also includes: A second blind hole is formed in the intermediate body, and the second blind hole and the first blind hole are located on different surfaces of the intermediate body, respectively. as well as A second conductive element is formed in the second blind via, and the second conductive element is electrically connected to the third conductive layer and the fourth conductive layer.

6. A circuit board connection structure, characterized in that, include: A first circuit board, the first circuit board including a first base layer, a first protective layer and at least one first conductive line layer located between the first base layer and the first protective layer; The second circuit board includes a second base layer, a second protective layer, and at least one second conductive line layer located between the second base layer and the second protective layer. A colloid, located between the first circuit board and the second circuit board, the colloid serving to connect one side of the first circuit board and one side of the second circuit board; and A first covering film is located on one surface of the colloid; The circuit board connection structure includes a first conductive element that penetrates the first covering film. The first conductive element is used to electrically connect the first conductive circuit layer and the second conductive circuit layer, so that the first circuit board and the second circuit board are electrically connected.

7. The circuit board connection structure as described in claim 6, characterized in that, The first conductive line layer includes a first solder pad, and the first solder pad is located at one end of the first conductive line layer. The second conductive line layer includes a second solder pad, and the second solder pad is located at one end of the second conductive line layer. The first conductive element is used to electrically connect the first solder pad and the second solder pad.

8. The circuit board connection structure as described in claim 6, characterized in that, Also includes: The surface of the first covering film away from the first base layer, the surface of the first protective layer away from the first base layer, and the surface of the second protective layer away from the second base layer are all flush.

9. The circuit board connection structure as described in claim 6, characterized in that, The first circuit board further includes a third protective layer and at least one third conductive layer. The third protective layer is located on the side of the first base layer away from the first protective layer, and the third conductive layer is located between the first base layer and the third protective layer. The second circuit board further includes a fourth protective layer and at least one fourth conductive layer. The fourth protective layer is located on the side of the second base layer away from the second protective layer, and the fourth conductive layer is located between the second base layer and the fourth protective layer.

10. The circuit board connection structure as described in claim 9, characterized in that, The circuit board connection structure also includes a second conductive element, which is located on a different surface from the first conductive element. The second conductive element is used to electrically connect the third conductive layer and the fourth conductive layer.

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