Circuit board and method for manufacturing the same

Abstract

A circuit board comprises a first substrate layer, an inner circuit layer, a circuit substrate and a plurality of first conductive bodies, wherein the inner circuit layer is arranged on one side of the first substrate layer, a first opening is arranged through the substrate layer, a part of the inner circuit layer is exposed at the bottom of the first opening, the first conductive body is arranged in the first opening, the first conductive body is electrically connected to the inner circuit layer, each of the first conductive bodies has a connection end face away from the inner circuit layer, a plurality of the connection end faces are exposed from the first substrate layer, the height difference between each two connection end faces does not exceed 3 microns, and the circuit substrate is arranged on the connection end faces. The circuit board provided in the present application can reduce the risk of empty soldering and improve the stability of the electrical connection between the first conductive body and the circuit substrate. 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] Hot bar soldering is a technology that can connect flexible boards and rigid boards together. The general process of this technology includes: first, setting the solder paste on multiple pads of the rigid board, then placing the flexible board on the pads with the solder paste, and finally heating it into molten solder paste through a hot press head. After the molten solder paste cools and solidifies, the electrical connection between the flexible board and the rigid board can be achieved.

[0003] However, the hot-pressed tin melting welding technology has high requirements for the flatness of the end surfaces of each welding pad. For example, for two welding pads with a large difference in end surface height (height difference greater than 30 microns), the welding pad with a smaller height may not be able to be welded to the flexible board, resulting in empty welding, which is not conducive to the stable electrical connection between the flexible board and the rigid board. Summary of the invention

[0004] In order to solve the problem in the background technology, the present application provides a circuit board.

[0005] In addition, the present application also provides a method for manufacturing a circuit board.

[0006] A method for manufacturing a circuit board includes the following steps: providing a double-sided copper-clad substrate, the double-sided copper-clad substrate including a first substrate layer, a first copper foil layer and a second copper foil layer, the first copper foil layer and the second copper foil layer are respectively arranged on two opposite surfaces of the first substrate layer, the double-sided copper-clad substrate is provided with a plurality of first openings at intervals, the first openings penetrate the first copper foil layer, the first substrate layer and the second copper foil layer. A first electroplating layer and a second electroplating layer are respectively arranged on the first copper foil layer and the second copper foil layer, a part of the first electroplating layer or a part of the second electroplating layer is filled into the first opening to form a first conductive body, each of the first conductive bodies has a connection end face connected to the first electroplating layer, and the height difference between each two of the connection end faces does not exceed 3 microns.

[0007] The second electroplating layer and the second copper foil layer are etched to form an inner circuit layer, and the first conductive body is electrically connected to the inner circuit layer. The first copper foil layer and the first electroplating layer are removed so that the plurality of connection end faces are exposed on the first substrate layer, and a circuit substrate is arranged on the plurality of end faces, and the first conductive body is electrically connected to the circuit substrate to obtain the circuit board.

[0008] Furthermore, before removing the first copper foil layer and the first electroplating layer, the steps include: arranging a single-sided copper-clad substrate on the inner circuit layer, the single-sided copper-clad substrate including a second substrate layer and a third copper foil layer, the second substrate layer being arranged between the third copper foil layer and the inner circuit layer, the single-sided copper-clad substrate being provided with a second opening, the second opening penetrating the second substrate layer and the third copper foil layer, and a portion of the inner circuit layer being exposed at the bottom of the second opening. Arranging a third electroplating layer on the third copper foil layer, a portion of the third electroplating layer being filled into the second opening to form a second conductive body, the second conductive body being electrically connected to the inner circuit layer, and etching the third electroplating layer and the third copper foil layer to form an outer circuit layer, the second conductive body being electrically conductive to the outer circuit layer and the inner circuit layer.

[0009] Furthermore, the circuit substrate is arranged on the end surface by hot pressing tin melting welding.

[0010] Furthermore, before setting the circuit substrate, the method further includes removing a portion of the first base material layer around the first conductive body to form a first accommodating space, wherein the first accommodating space is used to accommodate excess solder generated during the hot pressing molten tin welding process.

[0011] Furthermore, before setting the circuit substrate, the method further includes the steps of: setting a second opening on the base material layer, partially exposing the inner circuit layer at the bottom of the second opening, and setting an electronic component in the second opening, the electronic component being electrically connected to the inner circuit layer.

[0012] Furthermore, before the circuit substrate and the electronic component are provided, the method further includes the step of providing a protective layer on the outer surface of the first conductive body and on the portion of the inner circuit layer exposed in the second opening.

[0013] A circuit board comprises a first substrate layer, an inner circuit layer, a circuit substrate and a plurality of first conductive bodies, wherein the inner circuit layer is arranged on one side of the first substrate layer, a first opening is provided through the substrate layer, a portion of the inner circuit layer is exposed at the bottom of the first opening, the first conductive body is arranged in the first opening, the first conductive body is electrically connected to the inner circuit layer, each of the first conductive bodies has a connection end face away from the inner circuit layer, a plurality of the connection end faces are exposed from the first substrate layer, a height difference between each two of the connection end faces does not exceed 3 microns, and the circuit substrate is arranged on the connection end face.

[0014] Furthermore, it also includes a second substrate layer, an outer circuit layer and a second conductor, the second substrate layer is arranged between the outer circuit layer and the inner circuit layer, the second substrate layer is penetrated by a second opening, the second conductor is arranged in the second opening, and the second conductor electrically connects the inner circuit layer and the outer circuit layer.

[0015] Furthermore, the first substrate layer is further provided with a first accommodating space, and the first accommodating space is arranged around the periphery of the first conductive body.

[0016] Furthermore, it also includes a second accommodating space and an electronic component, the second accommodating space is arranged on the first substrate layer, part of the inner circuit layer is exposed at the bottom of the second accommodating space, the electronic component is arranged in the second accommodating space, and the electronic component is electrically connected to the inner circuit layer.

[0017] Compared with the prior art, the manufacturing method of the circuit board provided in the present application is to set a first electroplating layer and a second electroplating layer on both sides of a double-sided copper-clad substrate, and partially fill the first electroplating layer or the second electroplating layer into the first opening to form a first conductive body, and then expose the connection end surface of the first conductive body through the first copper foil layer and the first electroplating layer on one side of the first conductive body, and the height difference of the exposed connection end surface is within microns, thereby ensuring that the connection end surface is neat, reducing the risk of empty soldering, and improving the stability of the electrical connection between the first conductive body and the circuit substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of a double-sided copper-clad substrate provided in an embodiment of the present application.

[0019] Figure 2 for Figure 1 The schematic diagram shown is a double-sided copper clad substrate after a first conductive body is provided.

[0020] Figure 3 For etching Figure 2 A schematic diagram of a second electroplating layer and a second copper foil layer forming an inner circuit layer is shown.

[0021] Figure 4 for Figure 3 A schematic diagram of a single-sided copper-clad substrate being arranged on the inner circuit layer is shown.

[0022] Figure 5 For etching Figure 4 A schematic diagram of the third electroplating layer and the third copper foil layer after forming the outer circuit layer.

[0023] Figure 6 for Figure 5 Schematic diagram of setting a solder mask layer on the outer circuit layer shown.

[0024] Figure 7 for Figure 6 The schematic diagram shown is a first substrate layer provided with a first accommodating space and a second accommodating space.

[0025] Figure 8 for Figure 7 The schematic diagram shows a first conductive body with a protective layer disposed on the periphery and part of the inner circuit layer.

[0026] Fig. 9 for Figure 8 The schematic diagram is shown after electronic components are arranged on the inner circuit layer of the part where the protective layer is arranged.

[0027] Fig.10 A schematic diagram of a circuit board provided in an embodiment of the present application.

[0028] Main component symbols

[0029] Circuit board 100

[0030] Double-sided copper clad substrate 10

[0031] First base material layer 11

[0032] The first copper foil layer 12

[0033] The second copper foil layer 13

[0034] The first opening 14

[0035] First electroplating layer 21

[0036] Second electroplating layer 22

[0037] First conductive body 31

[0038] Connection end face 311

[0039] Inner circuit layer 41

[0040] Single-sided copper clad substrate 50

[0041] Second base material layer 51

[0042] The third copper foil layer 52

[0043] Second opening 53

[0044] The third electroplating layer 61

[0045] The second conductive body 62

[0046] Outer circuit layer 71

[0047] Wire Trough 711

[0048] Solder mask 81

[0049] Protective layer 82

[0050] Electronic components83

[0051] Circuit board 90

[0052] Solder layer 91

[0053] The first accommodating space D

[0054] The second accommodating space E

[0055] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0056] 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.

[0057] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element or can be simultaneously present in a central element. When an element is considered to be "disposed on" another element, it can be directly disposed on the other element or can be simultaneously present in a central element.

[0058] See also Figures 1 to 10 The present application provides a method for manufacturing a circuit board 100, comprising the steps of:

[0059] S1: Please see Figure 1 , a double-sided copper clad substrate 10 is provided, the double-sided copper clad substrate 10 comprises a first substrate layer 11, a first copper foil layer 12 and a second copper foil layer 13. The first copper foil layer 12 and the second copper foil layer 13 are respectively arranged on two opposite surfaces of the first substrate layer 11. The double-sided copper clad substrate 10 is provided with a plurality of first openings 14 at intervals, and the first openings 14 sequentially penetrate the first copper foil layer 12, the first substrate layer 11 and the second copper foil layer 13.

[0060] In the present embodiment, the material of the first substrate layer 11 includes but is not limited to polyimide (PI), polyester resin (PET), polyethylene naphthalate diformic acid glycol ester (PEN), liquid crystal polymer (LCP) and modified polyimide (MPI). Preferably, the material of the first substrate layer 11 is polyimide.

[0061] S2: See Figure 2 A first electroplating layer 21 is disposed on the first copper foil layer 12, and a second electroplating layer 22 is disposed on the second copper foil layer 13. Part of the first electroplating layer 21 or part of the second electroplating layer 22 is filled into the first opening 14 to form a first conductive body 31. Each of the first conductive bodies 31 has a connecting end face 311 connected to the first electroplating layer 21, and the height difference between each two connecting end faces 311 does not exceed 3 microns.

[0062] S3: See Figure 3 , the second electroplating layer 22 and the second copper foil layer 13 are etched to form an inner circuit layer 41 , and the first conductive body 31 is electrically connected to the inner circuit layer 41 .

[0063] In this example, see Figures 4 to 6 The method for manufacturing the circuit board 100 further comprises the steps of:

[0064] S31: See Figure 4 A single-sided copper-clad substrate 50 is disposed on the inner circuit layer 41, and the single-sided copper-clad substrate 50 includes a second substrate layer 51 and a third copper foil layer 52. The second substrate layer 51 is disposed between the third copper foil layer 52 and the inner circuit layer 41, and the single-sided copper-clad substrate 50 is provided with a second opening 53, which penetrates the second substrate layer 51 and the third copper foil layer 52, and a portion of the inner circuit layer 41 is exposed at the bottom of the second opening 53.

[0065] S32: See Figure 4 A third electroplating layer 61 is disposed on the third copper foil layer 52 , and a portion of the third electroplating layer 61 is filled into the second opening 53 to form a second conductive body 62 , and the second conductive body 62 is electrically connected to the inner circuit layer 41 .

[0066] S33: See Figure 5, the third electroplating layer 61 and the third copper foil layer 52 are etched to form an outer circuit layer 71 , and the second conductive body 62 electrically connects the outer circuit layer 71 and the inner circuit layer 41 .

[0067] S34: See Figure 6 A solder mask 81 is disposed on the outer circuit layer 71 , and a portion of the solder mask 81 is filled into the wire groove 711 of the outer circuit layer 71 .

[0068] S4: See Figure 7 The first copper foil layer 12 and the first electroplating layer 21 are removed by laser etching or chemical etching, so that the plurality of connection end faces 311 are exposed on the first substrate layer 11 , and the first substrate layer 11 can be provided on the inner circuit layer 41 as a covering protective layer.

[0069] In this example, see Figures 7 to 9 The method for manufacturing the circuit board 100 further comprises the steps of:

[0070] S41: See Figure 7 , a portion of the first substrate layer 11 around the first conductive body 31 is removed by laser cutting or chemical etching to form a first annular accommodating space D, and the first accommodating space D can be used to accommodate excess solder to prevent bridge short circuit caused by excess solder.

[0071] S42: See Figure 7 , a second accommodating space E is provided on the first substrate layer 11 , and a portion of the inner circuit layer 41 is exposed at the bottom of the second accommodating space E;

[0072] S43: See Figure 8 A protective layer 82 is disposed on the outer surface of the first conductive body 31 and the portion of the inner circuit layer 41 exposed in the second accommodating space E. The protective layer 82 can be formed by any one of gold plating, gold plating, nickel plating or tin plating.

[0073] S43: See Fig. 9 An electronic component 83 is disposed in the second accommodating space E, and the electronic component 83 is electrically connected to the inner circuit layer 41 provided with the protection layer 82 .

[0074] S5: See Fig.10A circuit substrate 90 is arranged on the connecting end surface 311 provided with a protective layer 82 by means of hot pressing tin melting welding, a solder layer 91 is arranged between the circuit substrate 90 and the protective layer 82, the solder layer 91 electrically connects the first conductive body 31 and the circuit substrate 90, and the circuit board 100 is obtained. The protective layer 82 and the circuit substrate 90 are directly connected by means of hot pressing tin melting welding, the connector is omitted, and the cost can be saved. Moreover, the height of the first conductive body 31 can be adjusted according to the thickness of the first base material layer 11, which is conducive to making a first conductive body 31 with a smaller height, thereby reducing the overall thickness of the circuit board 100.

[0075] Compared with the prior art, the manufacturing method of the circuit board 100 provided in the present application has the following advantages:

[0076] (i) A first electroplating layer 21 and a second electroplating layer 22 are provided on both sides of a double-sided copper clad substrate 10, and a portion of the first electroplating layer 21 or the second electroplating layer 22 is filled into the first opening 14 to form a first conductive body 31, and then a first copper foil layer 12 and the first electroplating layer 21 on one side of the first conductive body 31 are exposed, and the height difference of the exposed connecting end surface 311 is within 3 microns, thereby ensuring that the connecting end surface 311 is neat, reducing the risk of empty soldering, and improving the stability of the electrical connection between the first conductive body 31 and the circuit substrate 90.

[0077] (ii) The first conductive body 31 is formed by first filling the first opening 14, and then an inner circuit layer 41 is formed by etching on one side of the first conductive body 31, so that the inner circuit layer 41 can be made into a fine circuit with a small pitch, which is beneficial to the high integration of the circuit board 100.

[0078] See also Fig.10 The embodiment of the present application further provides a circuit board 100, the circuit board 100 includes a first substrate layer 11, an inner circuit layer 41, a circuit substrate 90 and a plurality of first conductive bodies 31, the inner circuit layer 41 is arranged on one side of the first substrate layer 11, the first substrate layer 11 is penetrated by a first opening 14, a portion of the inner circuit layer 41 is exposed at the bottom of the first opening 14, the first conductive body 31 is arranged in the first opening 14, the first conductive body 31 is electrically connected to the inner circuit layer 41, each of the first conductive bodies 31 has a connection end face 311 away from the inner circuit layer 41, a plurality of the connection end faces 311 are exposed from the first substrate layer 11, the height difference between each two of the connection end faces 311 does not exceed 3 microns, and the circuit substrate 90 is arranged on the connection end face 311.

[0079] See also Fig.10In this embodiment, the circuit board 100 further includes a second substrate layer 51, an outer circuit layer 71 and a second conductive body 62. The second substrate layer 51 is disposed between the outer circuit layer 71 and the inner circuit layer 41. A second opening 53 is provided through the second substrate layer 51. The second conductive body 62 is disposed in the second opening 53. The second conductive body 62 electrically connects the inner circuit layer 41 and the outer circuit layer 71.

[0080] See also Fig.10 In this embodiment, the first substrate layer 11 is further provided with a first accommodation space D and a second accommodation space E, wherein the first accommodation space D is provided around the periphery of the first conductive body 31. The second accommodation space E penetrates the first substrate layer 11, and a portion of the inner circuit layer 41 is exposed at the bottom of the second accommodation space E. The electronic component 83 is provided in the second accommodation space E, and the electronic component 83 is electrically connected to the inner circuit layer 41.

Claims

1. A method for manufacturing a circuit board, characterized in that: Includes steps: A double-sided copper-clad substrate is provided, the double-sided copper-clad substrate comprising a first substrate layer, a first copper foil layer and a second copper foil layer, the first copper foil layer and the second copper foil layer are respectively arranged on two opposite surfaces of the first substrate layer, the double-sided copper-clad substrate is provided with a plurality of first openings at intervals, and the first openings penetrate the first copper foil layer, the first substrate layer and the second copper foil layer; A first electroplating layer and a second electroplating layer are respectively disposed on the first copper foil layer and the second copper foil layer, and a portion of the first electroplating layer or a portion of the second electroplating layer is filled into the first opening to form a first conductive body, each of the first conductive bodies has a connecting end surface connected to the first electroplating layer, and a height difference between each two connecting end surfaces is less than or equal to 3 microns; Etching the second electroplating layer and the second copper foil layer to form an inner circuit layer, wherein the first conductive body is electrically connected to the inner circuit layer; removing the first copper foil layer and the first electroplating layer so that the plurality of connection end surfaces are exposed from the first substrate layer; as well as A circuit substrate is arranged on the plurality of connection end surfaces by hot pressing and tin melting welding, and the first conductive body is electrically connected to the circuit substrate to obtain the circuit board; Before removing the first copper foil layer and the first electroplating layer, the method further comprises the following steps: A single-sided copper-clad substrate is arranged on the inner circuit layer, the single-sided copper-clad substrate comprises a second substrate layer and a third copper foil layer, the second substrate layer is arranged between the third copper foil layer and the inner circuit layer, the single-sided copper-clad substrate is provided with a second opening, the second opening passes through the second substrate layer and the third copper foil layer, and a portion of the inner circuit layer is exposed at the bottom of the second opening; Disposing a third electroplating layer on the third copper foil layer, partially filling the third electroplating layer into the second opening to form a second conductive body, wherein the second conductive body is electrically connected to the inner circuit layer; and Etching the third electroplating layer and the third copper foil layer to form an outer circuit layer, wherein the second conductive body electrically connects the outer circuit layer and the inner circuit layer; Wherein, before setting the circuit substrate, the method further includes the following steps: Removing a portion of the first substrate layer around the first conductive body to form a first accommodating space, wherein the first accommodating space is used to accommodate excess solder generated during hot pressing molten tin soldering; Wherein, before setting the circuit substrate, the method further includes the following steps: A second accommodating space is provided on the substrate layer, and a portion of the inner circuit layer is exposed at the bottom of the second accommodating space; An electronic component is arranged in the second accommodation space, wherein the electronic component is electrically connected to the inner circuit layer; Wherein, before setting the circuit substrate and the electronic components, the method further includes the following steps: A protection layer is disposed on the outer surface of the first conductive body and on a portion of the inner circuit layer exposed in the second opening.

2. A circuit board manufactured by the method for manufacturing a circuit board according to claim 1, characterized in that: It includes a first substrate layer, an inner circuit layer, a circuit substrate and a plurality of first conductors, wherein the inner circuit layer is arranged on one side of the first substrate layer, a first opening is arranged through the substrate layer, a portion of the inner circuit layer is exposed at the bottom of the first opening, the first conductor is arranged in the first opening, the first conductor is electrically connected to the inner circuit layer, each of the first conductors has a connection end face away from the inner circuit layer, a plurality of the connection end faces are exposed from the first substrate layer, a height difference between each two of the connection end faces does not exceed 3 microns, and the circuit substrate is arranged on the connection end face.

3. The circuit board according to claim 2, characterized in that: It also includes a second substrate layer, an outer circuit layer and a second conductor, wherein the second substrate layer is arranged between the outer circuit layer and the inner circuit layer, the second substrate layer is penetrated by a second opening, the second conductor is arranged in the second opening, and the second conductor electrically connects the inner circuit layer and the outer circuit layer.

4. The circuit board according to claim 2, characterized in that: The first substrate layer is further provided with a first accommodating space, and the first accommodating space is arranged around the periphery of the first conductive body.

5. The circuit board according to claim 2, characterized in that: It also includes a second accommodating space and an electronic component. The second accommodating space is arranged on the first substrate layer. Part of the inner circuit layer is exposed at the bottom of the second accommodating space. The electronic component is arranged in the second accommodating space and is electrically connected to the inner circuit layer.

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