Circuit board connection structure and method of manufacturing the same

Abstract

A manufacturing method of a circuit board connecting structure and the circuit board connecting structure, the method comprising: providing a first circuit board comprising a first connecting pad; disposing conductive paste on the first connecting pad; disposing a conductive column on the conductive paste, so that the conductive paste flows and further covers the conductive column; providing a second circuit board comprising a second connecting pad; stacking the first circuit board and the second circuit board, so that the second connecting pad is located at an end of the conductive column away from the first connecting pad; and pressing the first circuit board and the second circuit board, so that the conductive paste flows and further covers the second connecting pad, the conductive paste comprising a first conductive paste layer covering the first connecting pad, a second conductive paste layer covering the conductive column, and a third conductive paste layer covering the second connecting pad, to obtain the circuit board connecting structure. The manufacturing method of the circuit board connecting structure simplifies the process and improves the yield of the circuit board connecting structure.

Description

TECHNICAL FIELD

[0001] The present application relates to a printed circuit board technology, and more particularly, to a circuit board connecting structure and a manufacturing method thereof. BACKGROUND

[0002] With the wide application of printed circuit boards in the electronic field, two or more circuit boards with different functions are usually integrated together to achieve the multi-functionality of electronic products.

[0003] The traditional connecting method mostly adopts the pulse hot bar connection. The general process of the pulse hot bar connection usually requires surface treatment of the solder pad, and then copper plating is performed on the solder pad to form a copper column, which is connected with other circuit boards through the copper column. The process of electroplating the copper column includes dry film pressing, exposure, development, etching, and film stripping. Since the height of the copper column is usually more than 50 μm, the thickness of the dry film should be at least 70 μm. However, the over-thick dry film has insufficient resolution capability for lines in different areas, especially fine lines, so multiple dry film pressing, exposure, development, etching, and film stripping are required to form the required copper column. Moreover, during soldering, the solder accumulates around the solder pad, which is easy to form a short circuit with the surrounding lines, affecting the product yield. SUMMARY

[0004] Therefore, in order to overcome at least one of the above-mentioned defects, it is necessary to provide a manufacturing method of a circuit board connecting structure.

[0005] In addition, the present application also provides a circuit board connecting structure manufactured by the above manufacturing method.

[0006] The present application provides a manufacturing method of a circuit board connecting structure, comprising the steps of:

[0007] providing a first circuit board, wherein the first circuit board comprises a first circuit layer, and the first circuit layer comprises a first connecting pad.

[0008] forming conductive paste on the first connecting pad.

[0009] providing a second circuit board, wherein the second circuit board comprises a second circuit layer, and the second circuit layer comprises a second connecting pad.

[0010] stacking the first circuit board and the second circuit board, so that the second connecting pad is located at one end of the conductive column away from the first connecting pad.

[0011] stacking the first circuit board and the second circuit board, so that the second connecting pad is located at one end of the conductive column away from the first connecting pad.

[0012] and, pressing the first circuit board and the second circuit board, so that the conductive paste channel and further cover the second connecting pad, the conductive paste includes a first conductive paste layer covering the first connecting pad, a second conductive paste layer covering the conductive column and a third conductive paste layer covering the second connecting pad, thereby obtaining the circuit board connecting structure.

[0013] In the embodiment, after the conductive column is arranged on the conductive paste, the manufacturing method further comprises: reflow soldering the first circuit board with the conductive column. After the first circuit board and the second circuit board are pressed, the manufacturing method further comprises: melting the conductive paste by hot-pressing tin soldering.

[0014] In the embodiment, a first transition layer is formed between the first conductive paste layer and the first connecting pad; a second transition layer is formed between the second conductive paste layer and the conductive column; and a third transition layer is formed between the third conductive paste layer and the second connecting pad.

[0015] In the embodiment, the first circuit layer further comprises a third connecting pad, and the manufacturing method further comprises:

[0016] An electronic component is mounted on the third connecting pad.

[0017] In the embodiment, the height of the conductive column is 30-300 μm, and the size of the cross section of the conductive column along the extension direction of the first circuit board or the second circuit board is 100-300 μm.

[0018] In the embodiment, before the conductive column is arranged on the conductive paste, the manufacturing method further comprises:

[0019] A surface treatment layer is formed on the surface of the conductive column.

[0020] The application also provides a circuit board connecting structure, which comprises a first circuit board and a second circuit board arranged in a stack, the first circuit board and the second circuit board are electrically connected by a conductive column, the first circuit board comprises a first circuit layer, the first circuit layer comprises a first connecting pad, the surface of the first connecting pad is provided with a first conductive paste layer, the conductive column is arranged on the surface of the first conductive paste layer, the surface of the conductive column is provided with a second conductive paste layer, the second circuit board comprises a second circuit layer, the second circuit layer comprises a second connecting pad, the second connecting pad is arranged on the surface of the second conductive paste layer and located at one end of the conductive column away from the first connecting pad, and the surface of the second connecting pad is provided with a third conductive paste layer.

[0021] In this embodiment of the application, the height of the conductive post is 30μm-300μm, and the cross-sectional dimension of the conductive post along the extension direction of the first circuit board or the second circuit board is 100μm-300μm.

[0022] In this embodiment of the application, a first transition layer is formed between the first conductive paste layer and the first connecting pad; a second transition layer is formed between the second conductive paste layer and the conductive post; and a third transition layer is formed between the third conductive paste layer and the second connecting pad.

[0023] In this embodiment of the application, the surface of the conductive post is provided with a surface treatment layer.

[0024] Compared to existing technologies, the manufacturing method of the circuit board connection structure of the present invention uses surface mount technology to attach conductive pillars to the first connection pad of the first circuit board, while simultaneously coating the conductive pillars with conductive paste. This eliminates the need for electroplating to form copper plating on the first connection pad, and also eliminates the need for soldering the conductive pillars to the first connection pad. This simplifies the process of setting conductive pillars on the first circuit board and avoids short circuits caused by solder accumulation during the soldering process. Furthermore, the width and height of the conductive pillars are easy to control, making it convenient to set conductive pillars for thin lines, improving the connection quality between circuit boards with thin lines, and increasing the yield of the circuit board connection structure. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the first circuit board provided in an embodiment of the present invention.

[0026] Figure 2 In order to be in Figure 1 The diagram shows a first cover film attached to a first circuit board.

[0027] Figure 3 In order to be in Figure 2 The diagram shows a first connecting pad with conductive paste applied.

[0028] Figure 4 In order to be in Figure 3 The diagram shows a conductive paste with conductive pillars.

[0029] Figure 5 for Figure 4 The diagram shows a further coating of conductive paste onto the conductive pillars.

[0030] Figure 6 This is a schematic diagram of the structure of the second circuit board provided in an embodiment of the present invention.

[0031] Figure 7 This is a schematic diagram of a circuit board connection structure provided in an embodiment of the present invention.

[0032] Figure 8A structural diagram of a circuit board connecting structure according to another embodiment of the present application.

[0033] Figure 9 A structural diagram of a circuit board connecting structure according to another embodiment of the present application.

[0034] Explanation of main element symbols

[0035] Circuit board connecting structure 100, 200, 300

[0036] First circuit board 10

[0037] First base material layer 11

[0038] First surface 111

[0039] Second surface 112

[0040] First circuit layer 12

[0041] First connecting pad 121

[0042] Third connecting pad 122

[0043] Third circuit layer 14

[0044] Fourth circuit layer 15

[0045] First cover film 16

[0046] First insulating adhesive layer 161

[0047] First dielectric layer 162

[0048] Second circuit board 20

[0049] Second base material layer 21

[0050] Second circuit layer 22

[0051] Second connecting pad 23

[0052] Second cover film 24

[0053] Second insulating adhesive layer 241

[0054] Second dielectric layer 242

[0055] Conductive paste 2

[0056] Conductive pillar 3

[0057] First transition layer 41

[0058] Second transition layer 42

[0059] Third transition layer 43

[0060] first conductive paste layer 51

[0061] second conductive paste layer 52

[0062] third conductive paste layer 53

[0063] surface treatment layer 6

[0064] electronic component 7

[0065] first circuit area A

[0066] first connection area B

[0067] second circuit area C

[0068] second connection area D

[0069] The following detailed description will further describe the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0070] The technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all.

[0071] 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 the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0072] The embodiments of the present application provide a manufacturing method of a circuit board connection structure 100, which specifically comprises the following steps:

[0073] Step S1, referring to Figure 1 , a first circuit board 10 is provided, which comprises a first substrate layer 11 and a first circuit layer 12 arranged on one surface of the first substrate layer 11. The first circuit layer 12 comprises a first connection pad 121 and a third connection pad 122.

[0074] The first substrate layer 11 comprises a first circuit area A and a first connection area B, the third connection pad 122 is arranged corresponding to the first circuit area A, and the first connection pad 121 is arranged corresponding to the first connection area B. The first connection area B is used for electrical connection with other circuit boards, and the first connection area B can be located in the middle of the first circuit board 10 or at the end of the first circuit board 10.

[0075] In the embodiment, the first connection region B is located at the edge of the first circuit region A, i.e., the first connection region B is located at the end of the first circuit board 10, i.e., the first connection pad 121 is located at the end of the first circuit board 10, facilitating subsequent connection with other circuit boards.

[0076] In the embodiment, the first circuit board 10 can be a single-layer board, a double-layer board or a multi-layer board.

[0077] In the embodiment, the first circuit board 10 is a multi-layer board, the first substrate layer 11 includes a first surface 111 and a second surface 112 opposite to the first surface 111, the first surface 111 is provided with the first circuit layer 12 and the first connection pad 121, the second surface 112 is provided with a third circuit layer 14 electrically connected with the first circuit layer 12, a surface of the third circuit layer 14 away from the first substrate layer 11 is provided with at least one fourth circuit layer 15 formed by build-up, and the fourth circuit layer 15 is electrically connected with the third circuit layer 14.

[0078] In the embodiment, the material of the first substrate layer 11 can be selected from one of resins such as epoxy resin, Prepreg (PP), BT resin, Polyphenylene Oxide (PPO), polyimide (PI), Polyethylene Terephthalate (PET) and Polyethylene Naphthalate (PEN).

[0079] In the embodiment, the material of the first substrate layer 11 is PI.

[0080] In step S2, referring to Figure 2 , a first cover film 16 is attached to the surface of the first circuit board 10, so that the first connection pad 121 and the third connection pad 122 are exposed on the first cover film 16.

[0081] In the embodiment, the first cover film 16 includes a first insulating adhesive layer 161 and a first dielectric layer 162. The first insulating adhesive layer 161 is arranged between the first dielectric layer 162 and the first circuit board 10.

[0082] In this embodiment, the material of the first dielectric layer 162 can be selected from one of the following resins: epoxy resin, Prepreg (PP), BT resin, Polyphenylene Oxide (PPO), polyimide (PI), Polyethylene Terephthalate (PET), and Polyethylene Naphthalate (PEN).

[0083] In this embodiment, the material of the first dielectric layer 162 is PI.

[0084] In this embodiment, the first cover film 16 is etched by exposure and development, thereby exposing the first connection pad 121 and the third connection pad 122.

[0085] Step S3, please refer to Figure 3 , the first connection pad 121 is provided with conductive paste 2.

[0086] In this embodiment, the conductive paste 2 can be tin paste.

[0087] In this embodiment, the conductive paste 2 is tin paste which is brushed on the surface of the first connection pad 121 by an automatic paste brushing machine, wherein the conductive paste 2 covers the top surface and the side surface of the first connection pad 121.

[0088] In this embodiment, the thickness of the conductive paste 2 on the top surface of the first connection pad 121 away from the first surface 111 is relatively thick, and the relatively thick tin paste is convenient for subsequent welding.

[0089] Step S4, please refer to Figure 4 and Figure 5 , the conductive paste 2 is provided with a conductive column 3, and the conductive paste 2 flows and further covers the conductive column 3.

[0090] In this embodiment, the conductive pillar 3 is mounted on the first connection pad 121 of the first circuit board 10 by using surface mounted technology (SMT). The conductive paste 2 printed on the first connection pad 121 will spread along the surface of the conductive pillar 3 under the action of heating in the reflow furnace, and completely cover the exposed surface of the conductive pillar 3. The conductive pillar 3 is mounted by using SMT technology, without the need for surface treatment of the first connection pad 121, and without the need for forming copper plating on the first connection pad 121 by electroplating, thereby simplifying the process and avoiding short circuit between the solder and the surrounding circuit in the electroplating process. The width and height of the conductive pillar 3 are easy to control, which facilitates the connection of the conductive pillar 3 to thin circuit lines. When mounting the conductive pillar 3, the amount of conductive paste 2 is easy to control, and will not overflow to the edge and cause short circuit with the first circuit layer 12.

[0091] In this embodiment, during the reflow soldering process, the conductive paste 2 will react with the metal surfaces of the conductive pillar 3 and the first connection pad 121 to form the first transition layer 41 and the second transition layer 42, respectively, due to heating. Specifically, the first transition layer 41 and the second transition layer 42 can be intermetallic compounds (IMC).

[0092] In this embodiment, before reflow soldering, the surface of the conductive pillar 3 can be pre-formed with a surface treatment layer 6 by surface treatment, and the conductive pillar 3 can be surface treated by using a copper protection agent (such as an Organic Solderability Preservatives (OSP) copper protection agent), tin (Sn) / silver (Ag), or nickel / gold (Ni / Au).

[0093] In this embodiment, the conductive pillar 3 can be a copper pillar. Further, if the conductive pillar 3 is surface treated by using an OSP copper protection agent or Sn / Ag, the first transition layer 41 and the second transition layer 42 generated are mainly intermetallic compounds Cu6Sn5 and Cu3Sn generated by the reaction of copper and Sn; and if the conductive pillar 3 is surface treated by using Ni / Au, the first transition layer 41 and the second transition layer 42 generated are mainly intermetallic compounds Ni3Sn4 generated by the reaction of Sn and Ni / Au.

[0094] In this embodiment, the height of the conductive pillar 3 is 30 μm-300 μm, and the cross-sectional dimension of the conductive pillar 3 along the extension direction of the first circuit board 10 is 100 μm-300 μm.

[0095] In this embodiment, the conductive pillar 3 can be a cylinder, or a cuboid or a square, etc.

[0096] In this embodiment, the electronic component 7 can be mounted on the third connection pad 122 simultaneously when the conductive pillar 3 is mounted, further simplifying the manufacturing process of the circuit board.

[0097] At step S5, referring to Figure 6 , a second circuit board 20 is provided, which includes a second substrate layer 21 and a second circuit layer 22 disposed on one surface of the second substrate layer 21, and the second circuit layer 22 includes a second connection pad 221.

[0098] The second substrate layer 21 includes a second circuit area C and a second connection area D, and the second connection pad 23 is disposed corresponding to the second connection area D. The second connection area D can be located in the middle of the second circuit board 20, or can be located at the end of the second circuit board 20.

[0099] In this embodiment, the second connection area D is located at the edge of the second circuit area C, that is, the second connection area D is located at the end of the second circuit board 20, and the second connection pad 23 is located at the end of the second circuit board 20.

[0100] In this embodiment, the second circuit board 20 can be a single-layer board, a double-layer board, or a multi-layer board. Specifically, the second circuit board 20 is a multi-layer board.

[0101] In this embodiment, the second circuit board 20 has the same structure as the first circuit board 10, and will not be described in detail here.

[0102] In this embodiment, the material of the second substrate layer 21 can be selected from one of epoxy resin, Prepreg (PP), BT resin, Polyphenylene Oxide (PPO), polyimide (PI), Polyethylene Terephthalate (PET), and Polyethylene Naphthalate (PEN) resins.

[0103] In this embodiment, the material of the second substrate layer 21 is PI.

[0104] At step S6, referring to Figure 6 , a second cover film 24 is attached to the surface of the second circuit board 20, and the second connection pad 23 is exposed on the second cover film 24.

[0105] In this embodiment, the second cover film 24 includes a second insulating adhesive layer 241 and a second dielectric layer 242, and the second insulating adhesive layer 241 is located between the second circuit board 20 and the second dielectric layer 242.

[0106] In this embodiment, the material of the second dielectric layer 242 can be selected from one of the following resins: epoxy resin, Prepreg (PP), BT resin, Polyphenylene Oxide (PPO), polyimide (PI), Polyethylene Terephthalate (PET), and Polyethylene Naphthalate (PEN).

[0107] In this embodiment, the material of the second dielectric layer 242 is PI.

[0108] In this embodiment, the second cover film 24 is etched by exposure and development to expose the second connection pad 23.

[0109] In step S7, referring to Figure 7 , the first circuit board 10 and the second circuit board 20 are laminated, and the second connection pad 23 is located at the end of the conductive column 3 away from the first connection pad 121.

[0110] In this embodiment, the first circuit board 10 and the second circuit board 20 are connected, the first connection area B is located at the end of the first circuit board 10, the second connection area D is located at the end of the second circuit board 20, the first connection area B and the second connection area D are oppositely arranged, and the second connection pad 23 and the first connection pad 121 are oppositely arranged at the two ends of the conductive column 3.

[0111] In step S8, referring to Figure 7 , the first circuit board 10 and the second circuit board 20 are laminated, and the second connection pad 23 is located at the end of the conductive column 3 away from the first connection pad 121.

[0112] In the embodiment, the conductive paste 2 is melted by hot-pressing and soldering, and the second connecting pad 23 is welded to the end of the conductive column 3 away from the first connecting pad 121 by the melted conductive paste 2. During the welding process, the melted conductive paste 2 further covers the second connecting pad 23. Thus, the first connecting pad 121, the conductive column 3 and the second connecting pad 23 are all separated by the conductive paste 2 and do not directly contact each other, which is beneficial to improve the electrical connection performance between the first connecting pad 121, the conductive column 3 and the second connecting pad 23 and improve the yield of the circuit board connecting structure 100.

[0113] In the embodiment, a third transition layer 43 is formed between the third conductive paste layer 53 and the second connecting pad 23 during the hot-pressing and soldering process. Specifically, the third transition layer 43 is an intermetallic compound formed by the oxidation reaction between the surface metal of the conductive column 3 and the conductive paste 2.

[0114] In the embodiment, if OSP or Sn / Ag is used for surface treatment of the conductive column 3, the generated third transition layer 43 is mainly intermetallic compounds Cu6Sn5 and Cu3Sn generated by the reaction of copper and Sn; and if Ni / Au is used for surface treatment of the conductive column 3, the generated third transition layer 43 is mainly intermetallic compound Ni3Sn4 generated by the reaction of Sn and Ni.

[0115] Please refer to Figure 8 The manufacturing method of the circuit board connecting structure 200 provided by another embodiment of the present application can not set the third connecting pad 122 at the first circuit area A corresponding to the first circuit layer 12, but form at least one fourth circuit layer 15 by lamination, and then connect the first circuit board 10 and the second circuit board 20 to form the circuit board connecting structure 200 according to actual needs. In the embodiment, the thickness of the first connecting area B of the circuit board connecting structure 200 is relatively thin, which is beneficial to reduce the total thickness of the circuit board connecting structure 200 at the first connecting area B after the first connecting area B and the second connecting area D are pressed and connected. The manufacturing method of the circuit board connecting structure of the embodiment can reduce the total thickness of the circuit board connecting structure 200 as a whole, thereby meeting the use requirements and being beneficial to the thinning of electronic products. It can be understood that the second circuit area C of the second circuit board 20 can also be laminated by using a similar method.

[0116] Please refer to Figure 9In another embodiment of the circuit board connection structure 300 provided by the present application, according to actual needs, in the present embodiment, the first connection area B can be located at other parts of the first circuit board 10 except the end part (for example, located at the middle part of the first circuit board 10), the second connection area D can be located at other parts of the second circuit board 20 except the end part (for example, located at the middle part of the second circuit board 20), the first circuit board 10 and the second circuit board 20 are electrically connected by the conductive column 3, thereby obtaining the circuit board connection structure 300. In the present embodiment, in this way, the spatial arrangement of multiple circuit boards in the assembly process can be facilitated, and the space utilization of the assembly space can be improved.

[0117] Please refer to Figure 7 The present application also provides a circuit board connection structure 100, which comprises a first circuit board 10 and a second circuit board 20 arranged in a stack, and the first circuit board 10 and the second circuit board 20 are electrically connected by a conductive column 3. The first circuit board 10 comprises a first circuit layer 12, the first circuit layer 12 comprises a first connection pad 121, the surface of the first connection pad 121 is provided with a first conductive paste layer 51, and the conductive column 3 is arranged on the surface of the first conductive paste layer 51. The surface of the conductive column 3 is provided with a second conductive paste layer 52. The second circuit board 20 comprises a second circuit layer 22, the second circuit layer 22 comprises a second connection pad 23, and the second connection pad 23 is arranged on the surface of the second conductive paste layer 52 and located at one end of the conductive column 3 away from the first connection pad 121.

[0118] In the present embodiment, the first circuit board 10 comprises a first substrate layer 11, the first circuit layer 12 is arranged on one surface of the first substrate layer 11, the first substrate layer 11 comprises a first circuit area A and a first connection area B, the third connection pad 122 is arranged corresponding to the first circuit area A, and the first connection pad 121 is arranged corresponding to the first connection area B. The first connection area B is used for electrical connection with other circuit boards, and the first connection area B can be located at the middle part of the first circuit board 10 or at the end part of the first circuit board 10.

[0119] In the present embodiment, the first connection area B is located at the edge of the first circuit area A, that is, the first connection area B is located at the end part of the first circuit board 10, that is, the first connection pad 121 is located at the end part of the first circuit board 10, which is convenient for subsequent connection with other circuit boards.

[0120] In the present embodiment, the first connection pad 121 is a solder pad.

[0121] In the present embodiment, the first circuit board 10 can be a single-layer board, a double-layer board or a multi-layer board.

[0122] In the embodiment, the first circuit board 10 is a multilayer board, the first substrate layer 11 includes a first surface 111 and a second surface 112 opposite to the first surface 111, the first surface 111 is provided with a first circuit layer 12, the second surface 112 is provided with a third circuit layer 14 electrically connected with the first circuit layer 12, a surface of the third circuit layer 14 away from the first substrate layer 11 is provided with at least one fourth circuit layer 15 formed by build-up, and the fourth circuit layer 15 is electrically connected with the third circuit layer 14.

[0123] In the embodiment, the material of the first substrate layer 11 can be selected from one of resins such as epoxy resin, Prepreg (PP), BT resin, Polyphenylene Oxide (PPO), polyimide (PI), Polyethylene Terephthalate (PET), and Polyethylene Naphthalate (PEN).

[0124] In the embodiment, the material of the first substrate layer 11 is PI.

[0125] In the embodiment, the first conductive paste layer 51, the second conductive paste layer 52, and the third conductive paste layer 53 can be formed after solidification of tin paste.

[0126] In the embodiment, the surface of the conductive pillar 3 is provided with a surface treatment layer 6, and the material of the surface treatment layer 6 is a copper protection agent (for example, Organic Solderability Preservatives (OSP copper protection agent)), tin (Sn) / silver (Ag), or nickel / gold (Ni / Au).

[0127] In the embodiment, the first transition layer 41, the second transition layer 42, and the third transition layer 43, in particular, the first transition layer 41 and the second transition layer 42 can be intermetallic compounds.

[0128] In the embodiment, the conductive pillar 3 can be a copper pillar, for example, the material of the surface treatment layer 6 is OSP or Sn / Ag, the first transition layer 41, the second transition layer 42, and the third transition layer 43 are mainly intermetallic compounds Cu6Sn5 and Cu3Sn generated by the reaction of copper and Sn; for example, the material of the surface treatment layer 6 is Ni / Au, and the first transition layer 41, the second transition layer 42, and the third transition layer 43 are mainly intermetallic compounds Ni3Sn4 generated by the reaction of Sn and Ni.

[0129] In this embodiment, the height of the conductive pillar 3 is 30 μm-300 μm, and the cross-sectional dimension of the conductive pillar 3 along the extension direction of the first circuit board 10 is 100 μm-300 μm.

[0130] In this embodiment, the conductive pillar 3 can be a cylinder, or a cuboid or a square, etc.

[0131] In this embodiment, the first circuit board 10 and / or the second circuit board 20 is provided with an electronic element 7.

[0132] In this embodiment, the first circuit board 10 is provided with an electronic element 7, and the electronic element 7 is arranged on the third connection pad 122.

[0133] In this embodiment, the second circuit board 20 comprises a second substrate layer 21, and the second circuit layer 22 is arranged on one surface of the second substrate layer 21. The second substrate layer 21 comprises a second circuit area C and a second connection area D, and the second connection pad 23 is arranged corresponding to the second connection area D. The second connection area D can be located in the middle of the second circuit board 20, or can be located at the end of the second circuit board 20.

[0134] In this embodiment, the second connection area D is located at the edge of the second circuit area C, i.e. the second connection area D is located at the end of the second circuit board 20, and the second connection pad 23 is located at the end of the second circuit board 20.

[0135] In this embodiment, the second circuit board 20 can be a single-layer board, a double-layer board or a multi-layer board. Specifically, the second circuit board 20 is a multi-layer board.

[0136] In this embodiment, the second circuit board 20 has the same structure as the first circuit board 10, and will not be described in detail here.

[0137] In this embodiment, the material of the second substrate layer 21 can be selected from one of the following resins: epoxy resin, Prepreg (PP), BT resin, Polyphenylene Oxide (PPO), polyimide (PI), Polyethylene Terephthalate (PET), and Polyethylene Naphthalate (PEN), etc.

[0138] In this embodiment, the material of the second substrate layer 21 is PI.

[0139] In the embodiment, the first connecting area B is located at the end of the first circuit board 10, the second connecting area D is located at the end of the second circuit board 20, and the first connecting area B and the second connecting area D are oppositely stacked, and the second connecting pad 23 and the first connecting pad 121 are oppositely arranged at the two ends of the conductive column 3.

[0140] Referring to Figure 8 In another embodiment of the circuit board connecting structure 200 provided by the application, the difference from the above-mentioned circuit board connecting structure 100 is that, according to actual requirements, in the embodiment, the third connecting pad 122 can not be arranged at the first circuit area A of the first circuit layer 12, but at least one fourth circuit layer 15 is formed by the way of layer increasing. In the embodiment, the thickness of the first connecting area B of the circuit board connecting structure 200 is relatively thin, and after the first connecting area B and the second connecting area D are press-bonded, the total thickness of the circuit board connecting structure 200 at the corresponding first connecting area B is reduced, and the total thickness of the circuit board connecting structure 200 can be reduced as a whole, so that the use requirements can be met, and the thinning of the electronic product is facilitated. It can be understood that the second circuit area C of the second circuit board 20 can also be increased in layers.

[0141] Referring to Figure 9 In another embodiment of the circuit board connecting structure 300 provided by the application, the difference from the above-mentioned circuit board connecting structure 100 is that, according to actual requirements, the first connecting area B can be located at other parts (for example, the middle part) of the first circuit board 10 except the end, the second connecting area D can be located at other parts (for example, the middle part) of the second circuit board 20 except the end, and the first circuit board 10 and the second circuit board 20 are electrically connected by the conductive column 3 between the first connecting area B and the second connecting area D. In the embodiment, in this way, the space arrangement of multiple circuit boards during assembly can be facilitated, and the space utilization of the assembly space can be improved.

[0142] The manufacturing method of the circuit board connecting structure adopts the patch technology to mount the conductive column on the first connecting pad of the first circuit board, and the conductive paste is coated on the conductive column, so that the copper plating on the first connecting pad is not needed, and the conductive column is not needed to be welded on the first connecting pad by welding, the process of arranging the conductive column on the first circuit board is simplified, and the solder accumulation and short circuit between the surrounding lines during welding are avoided; and the width and height of the conductive column are easy to control, the conductive column is convenient to arrange for the fine lines, the connection quality between the fine line circuit boards is improved, and the yield of the circuit board connecting structure is improved.

Claims

1. A method of manufacturing a circuit board connection structure, characterized by, The method comprises the steps of: providing a first circuit board comprising a first circuit layer, the first circuit layer comprising a first connecting pad; providing conductive paste on the first connecting pad; providing a conductive column on the conductive paste, and performing reflow soldering on the first circuit board with the conductive column, so that the conductive paste flows and further covers the conductive column; providing a second circuit board comprising a second circuit layer, the second circuit layer comprising a second connecting pad; stacking the first circuit board and the second circuit board, so that the second connecting pad is located at an end of the conductive column away from the first connecting pad; and pressing the first circuit board and the second circuit board, so that the conductive paste is melted by hot-pressing tin soldering, the conductive paste flows and further covers the second connecting pad, the conductive paste comprises a first conductive paste layer covering the first connecting pad, a second conductive paste layer covering the conductive column, and a third conductive paste layer covering the second connecting pad, the first conductive paste layer, the second conductive paste layer, and the third conductive paste layer are integrated, a first transition layer is formed between the first conductive paste layer and the first connecting pad, a second transition layer is formed between the second conductive paste layer and the conductive column, and a third transition layer is formed between the third conductive paste layer and the second connecting pad, thereby obtaining the circuit board connecting structure.

2. The method of manufacturing a circuit board connection structure according to Claim 1, wherein The first circuit layer further comprises a third connecting pad, and the manufacturing method further comprises: mounting an electronic component on the third connecting pad.

3. The method of manufacturing a circuit board connection structure according to Claim 1, wherein The height of the conductive column is 30-300 microns, and the size of the cross section of the conductive column along the extension direction of the first circuit board or the second circuit board is 100-300 microns.

4. The method of manufacturing a circuit board connection structure according to Claim 1, wherein Before the conductive column is provided on the conductive paste, the manufacturing method further comprises: forming a surface treatment layer on the surface of the conductive column.

5. A circuit board connecting structure manufactured by the method of manufacturing a circuit board connecting structure according to Claim 1, characterized by, The method comprises the steps of: providing a first circuit board comprising a first circuit layer, the first circuit layer comprising a first connecting pad, the surface of the first connecting pad being provided with a first conductive paste layer, and a first transition layer being formed between the first conductive paste layer and the first connecting pad; providing a conductive column on the surface of the first conductive paste layer, the surface of the conductive column being provided with a second conductive paste layer, and a second transition layer being formed between the second conductive paste layer and the conductive column; providing a second circuit board stacked with the first circuit board, the second circuit board comprising a second circuit layer, the second circuit layer comprising a second connecting pad, the second connecting pad being provided on the surface of the second conductive paste layer and located at an end of the conductive column away from the first connecting pad, the surface of the second connecting pad being provided with a third conductive paste layer, a third transition layer being formed between the third conductive paste layer and the second connecting pad, and the first conductive paste layer, the second conductive paste layer, and the third conductive paste layer being integrated.

6. The circuit board connection structure according to claim 5, wherein The height of the conductive column is 30-300 microns, and the size of the cross section of the conductive column along the extension direction of the first circuit board or the second circuit board is 100-300 microns.

7. The circuit board connection structure according to claim 5, wherein The surface of the conductive column is provided with a surface treatment layer.

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