CN113840470A

CN113840470A - Circuit board and manufacturing method thereof

Info

Publication number: CN113840470A
Application number: CN202010592598.3A
Authority: CN
Inventors: 吴金成; 黄美华; 侯宁; 王化宁; 宋强; 李荣超
Original assignee: Avary Holding Shenzhen Co Ltd; Qing Ding Precision Electronics Huaian Co Ltd
Current assignee: Avary Holding Shenzhen Co Ltd; Qing Ding Precision Electronics Huaian Co Ltd
Priority date: 2020-06-24
Filing date: 2020-06-24
Publication date: 2021-12-24

Abstract

The application provides a circuit board, includes: the first substrate comprises a first surface and a second surface which are opposite to each other; the first circuit layer is arranged on the first surface and comprises a first connecting end and a first conductive circuit, the first conductive circuit is electrically connected with the first connecting end, and the material of the first conductive circuit comprises silver; the light-emitting unit and the first circuit layer are arranged on the same side of the first substrate, and the light-emitting unit is electrically connected with the first connecting end; and the second circuit layer is arranged on the second surface and is electrically connected with the first circuit layer. The application also provides a manufacturing method of the circuit board.

Description

Circuit board and manufacturing method thereof

Technical Field

The application relates to the technical field of circuit boards, in particular to a circuit board and a manufacturing method thereof.

Background

Along with the development of display technology, people demand screen resolution ratio more and more high, and demand gamut range more and more extensively, and the screen that demands high resolution ratio then need promote the pixel density of screen, need ask the screen to use LED lamp pearl of smaller size and the LED lamp pearl of more quantity, need ask the screen to have higher and more even LED light source reflection can satisfy the user to the demand of wide colour gamut simultaneously.

In the prior art, with the demand of screen resolution higher and higher, the size of the LED is smaller and smaller, the quantity of the LED is more and more, and the large quantity of small-size LEDs which are arranged on a backlight circuit board can lead the wiring density of the surface of the backlight board to be increased, the wiring density is increased, so that the copper-coated area of the surface is increased, the substrate area is reduced, and the reflectivity of the copper-coated area is smaller than that of the substrate area, so that the average level of the overall reflectivity of the backlight board is reduced.

How to solve the above problems needs to be considered by those skilled in the art.

Disclosure of Invention

In view of the above, the present application provides a circuit board, including:

the first substrate comprises a first surface and a second surface which are opposite to each other;

the first circuit layer is arranged on the first surface and comprises a first connecting end and a first conductive circuit, the first conductive circuit is electrically connected with the first connecting end, and the material of the first conductive circuit comprises silver;

the light-emitting unit and the first circuit layer are arranged on the same side of the first substrate, and the light-emitting unit is electrically connected with the first connecting end; and

and the second circuit layer is arranged on the second surface and is electrically connected with the first circuit layer.

In an embodiment, the circuit board further includes a solder resist layer, the solder resist layer covers a portion of the first circuit layer not covered by the light emitting unit, the solder resist layer covers a portion of the first surface not covered by the first circuit layer, and the solder resist layer covers the second circuit layer and a surface of the second surface not covered by the second circuit layer.

In an embodiment, the circuit board further includes a conductive hole, the conductive hole penetrates through the first connection end, the first substrate and the second circuit layer, and the conductive hole electrically connects the first connection end and the second circuit layer.

In one embodiment, the first connection end includes a first conductive layer and a first electroplated layer, the first conductive layer is disposed on the first surface, and the first electroplated layer is disposed on a side of the first conductive layer away from the first surface;

the second circuit layer comprises a second conductive layer and a second electroplated layer, the second conductive layer is arranged on the second surface, and the second electroplated layer is arranged on one side of the second conductive layer, which is far away from the second surface; and

the conductive hole comprises a via hole and a third electroplated layer, the third electroplated layer is arranged on the hole wall of the via hole, and the third electroplated layer is electrically connected with the first electroplated layer, the first conductive layer, the second electroplated layer and the second conductive layer respectively.

In an embodiment, a reflectivity of the first conductive line to light is greater than or equal to 95%.

The application also provides a manufacturing method of the circuit board, which comprises the following steps:

providing a double-sided board, wherein the double-sided board comprises a first substrate, and the first substrate comprises a first surface and a second surface which are opposite;

sequentially carrying out processes of punching, metallization and image transfer on the double-sided board, forming a first connecting end on the first surface, and forming a second circuit layer on the second surface, so that the first connecting end is electrically connected with the second circuit layer through a conductive hole;

arranging a silver-containing conductive material on the first surface, solidifying the silver-containing conductive material to obtain a first conductive circuit, and electrically connecting the first conductive circuit with the first connecting end; and

and providing a light-emitting unit to electrically connect the light-emitting unit with the first connecting end.

In one embodiment, the steps of sequentially performing the processes of punching, metallization and image transfer on the double-sided board are as follows:

the double-sided board comprises a first conducting layer and a second conducting layer which are respectively arranged on the first surface and the second surface;

forming a via hole penetrating through the double-sided board;

forming a first electroplated layer on the surface of the first conductive layer far away from the first base material, forming a second electroplated layer on the surface of the second conductive layer far away from the first base material, and forming a third electroplated layer on the surface of the hole wall of the through hole; and

and arranging a photoinduced anti-etching layer on the surfaces of the first electroplated layer and the second electroplated layer, which are far away from the first base material, developing and exposing the photoinduced anti-etching layer, etching the processed photoinduced anti-etching layer, and removing at least parts of the first conductive layer, the first electroplated layer, the second conductive layer and the second electroplated layer to obtain the first connecting end and the second circuit layer.

In one embodiment, the fabricating of the first conductive lines includes the following steps:

printing a silver-containing conductive material on the first surface, so that at least part of the silver-containing conductive material is overlapped with the first connection end; and

and carrying out heat treatment on the silver-containing conductive material to solidify the silver-containing conductive material to form the first conductive circuit.

In an embodiment, before providing the light emitting unit, the method further includes manufacturing a solder mask layer:

providing a solder resist material, wherein the solder resist material is arranged on the first surface and the second surface and covers the first connecting end, the first conducting circuit, the second circuit layer and the gap of the conducting hole;

pre-baking the solder resist material;

exposing and developing the pre-baked solder mask material to remove at least part of the solder mask material covering the first connecting end to obtain a mounting groove, so that at least part of the first connecting end is exposed from the mounting groove; and

and curing the solder resist material to obtain the solder resist layer.

In one embodiment, the method further comprises the following steps:

the surface of the first connecting end, which corresponds to the mounting groove, is a third surface, and the third surface is pretreated;

forming a first connection layer on the pre-processed third surface to electrically connect the first connection layer and the first connection end;

filling conductive paste in the mounting groove to form a second connecting layer, so that the second connecting layer is electrically connected with the first connecting layer; and

and providing the light-emitting unit, and electrically connecting the light-emitting unit with the second connecting layer.

Compared with the prior art, the circuit board and the manufacturing method thereof have the advantages that the first conducting circuit containing silver is arranged on the first surface, the first conducting circuit containing silver has higher light reflectivity and lower light absorptivity compared with the traditional copper conducting circuit, so that the reflection of light emitted by the light emitting unit on the circuit board is more uniform, the structure can realize high-efficiency reflection of the light without increasing the layer number of the circuit board, the manufacturing cost can be effectively reduced, and the product quality is improved.

Drawings

Fig. 1 is a schematic partial cross-sectional view of a circuit board according to an embodiment of the present application.

Fig. 2 is a schematic partial top view of a circuit board according to an embodiment of the present application.

Fig. 3 is a partial schematic view of a circuit board according to an embodiment of the present application.

Fig. 4 is a schematic view of a manufacturing process of a circuit board according to an embodiment of the present application.

Fig. 5 is a schematic view of a manufacturing process of a circuit board according to an embodiment of the present application.

Fig. 6 is a schematic view of a manufacturing process of a circuit board according to an embodiment of the present application.

Fig. 7 is a schematic view of a manufacturing process of a circuit board according to an embodiment of the present application.

Fig. 8 is a schematic view of a manufacturing process of a circuit board according to an embodiment of the present application.

Fig. 9 is a schematic view of a manufacturing process of a circuit board according to an embodiment of the present application.

Fig. 10 is a schematic view of a manufacturing process of a circuit board according to an embodiment of the present application.

Fig. 11 is a schematic view of a manufacturing process of a circuit board according to an embodiment of the present application.

Fig. 12 is a schematic view of a manufacturing process of a circuit board according to an embodiment of the present application.

Fig. 13 is a schematic view of a manufacturing process of a circuit board according to an embodiment of the present application.

Fig. 14 is a schematic view of a manufacturing process of a circuit board according to an embodiment of the present application.

Fig. 15 is a schematic view of a manufacturing process of a circuit board according to an embodiment of the present application.

Fig. 16 is a schematic view of a manufacturing process of a circuit board according to an embodiment of the present application.

Fig. 17 is a schematic view of a manufacturing process of a circuit board according to an embodiment of the present application.

Description of the main elements

Circuit board 1

First substrate 10

First surface 101

Second surface 102

Pad 109

First wiring layer 11

First connection end 111

First conductive layer 112

First plating layer 113

First conductive trace 115

Third surface 116

Second wiring layer 12

Second conductive layer 122

Second plating layer 123

Conductive via 13

Via 131

Third plating layer 132

Solder resist layer 14

Mounting groove 141

Connecting layer 15

First connection layer 151

Second connection layer 152

Light emitting unit 16

Double-sided board 21

Photoresist layer 22

Mask 23

Silver-containing conductive material 24

The following detailed description will further illustrate the present application in conjunction with the above-described figures.

Detailed Description

The following description will refer to the accompanying drawings to more fully describe the present disclosure. There is shown in the drawings exemplary embodiments of the present application. This application may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. These exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Like reference numerals designate identical or similar components.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Further, as used herein, the terms "comprises," "comprising," "includes" and/or "including" or "having" and/or "having," integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof.

Unless otherwise defined, all terms (including 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. Furthermore, unless otherwise defined herein, terms such as those defined in commonly used dictionaries should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present application and will not be interpreted in an idealized or overly formal sense.

The following description of exemplary embodiments refers to the accompanying drawings. It should be noted that the components depicted in the referenced drawings are not necessarily shown to scale; and the same or similar components will be given the same or similar reference numerals or similar terms.

Embodiments of the present application will now be described in further detail with reference to the accompanying drawings.

As shown in fig. 1 to 3, the present application provides a circuit board 1 including a first substrate 10, a first circuit layer 11, a second circuit layer 12, a conductive via 13, a solder resist layer 14, a connection layer 15, and a light emitting unit 16. The first circuit layer 11 and the second circuit layer 12 are disposed on two opposite sides of the first substrate 10, the solder resist layer 14 covers the exposed surfaces of the first circuit layer 11, the second circuit layer 12 and the first substrate 10, and the light emitting unit 16 is disposed on one side of the first circuit layer 11 away from the first substrate 10.

The first substrate 10 includes a first surface 101 and a second surface 102 opposite to each other, the first circuit layer 11 is disposed on the first surface 101, and the second circuit layer 12 is disposed on the second surface 102.

The first circuit layer 11 includes a first connecting end 111 and a first conductive trace 115, the first conductive trace 115 is electrically connected to the first connecting end 111, and a material of the first conductive trace 115 includes silver. The first conductive traces 115 may serve as connection lines of the wiring board 1.

In one embodiment, as shown in fig. 2, the light emitting unit 16 is electrically connected to a pad 109 through the first connection end 111 and the first conductive trace 115. In one embodiment, as shown in fig. 3, the first connecting end 111 may be trapezoidal, and the first connecting end 111 overlaps the first conductive trace 115.

In an embodiment, the first conductive traces 115 are formed by silver paste curing, and the reflectivity of the first conductive traces 115 to light is greater than or equal to 95%. In other embodiments, the first conductive traces 115 can also be other high-reflectivity conductive materials.

In one embodiment, the first connection end 111 includes a first conductive layer 112 and a first plating layer 113. The first conductive layer 112 is disposed on the first surface 101, and the first plating layer 113 is disposed on a side of the first conductive layer 112 away from the first surface 101.

The second circuit layer 12 is electrically connected to the first circuit layer 11.

In an embodiment, the second circuit layer 12 includes a second conductive layer 122 and a second plating layer 123, the second conductive layer 122 is disposed on the second surface 102, and the second plating layer 123 is disposed on a side of the second conductive layer 122 away from the second surface 102.

The conductive via 13 penetrates the first connection end 111, the first substrate 10 and the second circuit layer 12, and the conductive via 13 electrically connects the first connection end 111 and the second circuit layer 12.

In one embodiment, the conductive via 13 includes a via hole 131 and a third plating layer 132, the third plating layer 132 is disposed on the wall of the via hole 131, and the third plating layer 132 is electrically connected to the first plating layer 113, the first conductive layer 112, the second plating layer 123 and the second conductive layer 122, respectively.

The solder resist layer 14 covers a portion of the first circuit layer 11 not covered by the light emitting unit 16, the solder resist layer 14 covers a portion of the first surface 101 not covered by the first circuit layer 11, the solder resist layer 14 covers a surface of the second circuit layer 12 away from the first substrate 10, and the solder resist layer 14 covers a surface of the second surface 102 not covered by the second circuit layer 12.

In an embodiment, the solder mask layer 14 includes a mounting groove 141, the mounting groove 141 is a vacant area of the solder mask layer 14, the mounting groove 141 exposes at least a portion of the first connection end 111, and the mounting groove 141 can be disposed between two adjacent conductive vias 13.

In one embodiment, the solder mask layer 14 is a high reflectivity material, and the reflectivity of the solder mask layer 14 to light may be greater than 95%.

The connection layer 15 includes a first connection layer 151 and a second connection layer 152, the first connection layer 151 is disposed on a surface of the first connection end 111 not covered by the solder resist layer 14, the second connection layer 152 may be a conductive paste, and the second connection layer 152 may be filled in the mounting groove 141. In one embodiment, the second connection layer 152 may include two parts spaced apart from each other, the two parts spaced apart from each other are electrically connected to the first connection layer 151 on both sides of the mounting groove 141, respectively, and the light emitting unit 16 is electrically connected to the two parts, which can effectively prevent short circuit while ensuring electrical connection.

The light emitting unit 16 and the first circuit layer 11 are disposed on the same side of the first substrate 10, and the light emitting unit 16 is electrically connected to the first connection end 111, specifically, the light emitting unit 16 is electrically connected to the second connection layer 152, the second connection layer 152 is electrically connected to the first connection layer 151, and the first connection layer 151 is electrically connected to the first connection end 111.

As shown in fig. 4 to 17, the present application further provides a method for manufacturing a circuit board 1, including the following steps:

step S1: as shown in fig. 4, a dual-sided board 21 is provided, the dual-sided board 21 includes a first substrate 10, and the first substrate 10 includes a first surface 101 and a second surface 102 opposite to each other.

In one embodiment, the double-sided board 21 includes a first circuit layer 11 and a second circuit layer 12 respectively disposed on the first surface 101 and the second surface 102;

step S2: as shown in fig. 5 to 10, the double-sided board is sequentially processed by punching, metallization and image transfer processes, so as to form a first connection end 111 on the first surface 101 and a second circuit layer 12 on the second surface 102, such that the first connection end 111 and the second circuit layer 12 are electrically connected through a conductive hole 13;

step S21: as shown in fig. 5, a via hole 131 penetrating the double-sided board 21 is formed.

In an embodiment, the through holes 131 penetrating through the double-sided board 21 may be formed by laser, mechanical drilling, etching, and the like, and the number of the through holes 131 may be two.

Step S22: as shown in fig. 6, a first plating layer 113 is formed on the surface of the first conductive layer 112 remote from the first base 10, a second plating layer 123 is formed on the surface of the second conductive layer 122 remote from the first base 10, and a third plating layer 132 is formed on the wall surface of the via hole 131.

Step S23: as shown in fig. 7 to 10, the photoresist layer 22 is disposed on the surfaces of the first plating layer 113 and the second plating layer 123 far from the first substrate 10, the photoresist layer 22 is developed and exposed, and then the processed photoresist layer 22 is etched to remove at least portions of the first conductive layer 112, the first plating layer 113, the second conductive layer 122, and the second plating layer 123, thereby obtaining the first connection terminal 111 and the second line layer 12.

In one embodiment, as shown in fig. 7, a photoresist layer 22 is disposed on the surfaces of the first electroplating layer 113 and the second electroplating layer 123 far from the first substrate 10.

In one embodiment, as shown in fig. 8, the photoresist layer 22 is subjected to a developing etching process to deform a portion of the photoresist layer 22 for patterning.

In one embodiment, as shown in FIG. 9, portions of the photoresist layer 22 are removed to form a patterned mask 23.

In one embodiment, as shown in fig. 10, the first conductive layer 112, the first electroplated layer 113, the second conductive layer 122 and the second electroplated layer 123 are etched by using the patterned mask 23 as a mask to remove portions and obtain the first connection terminals 111 and the second circuit layers 12.

Step S3: as shown in fig. 11, the silver-containing conductive material 24 is disposed on the first surface 101, and the silver-containing conductive material 24 is cured to obtain the first conductive trace 115, so that the first conductive trace 115 is electrically connected to the first connection end 111.

The method specifically comprises the following steps:

the silver-containing conductive material 24 is printed on the first surface 101, so that at least a portion of the silver-containing conductive material 24 overlaps the first connection end 111.

The silver-containing conductive material 24 is cured by heat treatment (e.g., heating, baking) to form the first conductive traces 115.

Step S4: as shown in fig. 12 to 14, the solder resist layer 14 is formed.

Step S41: as shown in fig. 12, the solder resist material 25 is provided, such that the solder resist material 25 is disposed on the first surface 101 and the second surface 102 and covers the first connection end 111, the first conductive trace 115, the second trace layer 12 and the gap of the conductive via 13.

Step S42: the solder resist material 25 is pre-baked to obtain a preliminary fixed shape of the solder resist material 25, and during the pre-baking process, the hardness of the solder resist material 25 is increased by evaporation of a portion of the solvent in the solder resist material 25, but not to the maximum.

Step S43: as shown in fig. 13 and 14, the solder resist material 25 after the pre-baking is exposed and developed to remove at least a portion of the solder resist material 25 covering the first connection end 111 to obtain a mounting groove 141, so that at least a portion of the first connection end 111 is exposed from the mounting groove 141.

Step S44: as shown in fig. 14, the solder resist material 25 is cured by heat treatment again to obtain the solder resist layer 14.

Step S5: as shown in fig. 15 to 17, the light emitting unit 16 is provided, so that the light emitting unit 16 is electrically connected to the first connection end 111.

Step S51: as shown in fig. 15, the surface of the first connection end 111 corresponding to the mounting groove 141 is the third surface 116, and the third surface 116 is preprocessed. The pretreatment process can remove the residues on the third surface 116 during the etching process, and can improve the flatness and smoothness of the third surface 116, thereby improving the electrical connection quality of the first connection terminals 111.

Step S52: as shown in fig. 15, a first connection layer 151 is formed on the pre-processed third surface 116, such that the first connection layer 151 is electrically connected to the first connection terminals 111. In one embodiment, the first connection layer 151 may be formed by an electroplating or metallization process.

Step S53: as shown in fig. 16, the mounting groove 141 is filled with a conductive paste to form a second connection layer 152, so that the second connection layer 152 is electrically connected to the first connection layer 151.

In one embodiment, the second connection layer 152 may include two portions spaced apart from each other, and the two portions spaced apart from each other are electrically connected to the first connection layers 151 on two sides of the mounting groove 141, respectively.

Step S54: as shown in fig. 17, a light emitting unit 16 is provided, such that the light emitting unit 16 is electrically connected to the second connection layer 152.

In one embodiment, the light emitting unit 16 is electrically connected to the two portions, which can effectively avoid short circuit while ensuring electrical connection.

Hereinbefore, specific embodiments of the present application are described with reference to the drawings. However, those skilled in the art will appreciate that various modifications and substitutions can be made to the specific embodiments of the present application without departing from the spirit and scope of the application. Such modifications and substitutions are intended to be within the scope of the present application.

Claims

1. A circuit board, comprising:

2. The wiring board of claim 1, further comprising a solder resist layer covering a portion of the first wiring layer not covered by the light emitting unit, the solder resist layer covering a portion of the first surface not covered by the first wiring layer, the solder resist layer covering a surface of the second wiring layer remote from the first substrate and a surface of the second surface not covered by the second wiring layer.

3. The circuit board of claim 1, further comprising a conductive via that extends through the first connection end, the first substrate, and the second circuit layer, the conductive via electrically connecting the first connection end and the second circuit layer.

4. The wiring board of claim 3,

the first connecting end comprises a first conducting layer and a first electroplated layer, the first conducting layer is arranged on the first surface, and the first electroplated layer is arranged on one side, far away from the first surface, of the first conducting layer;

5. The circuit board of claim 1, wherein the first conductive traces have a light reflectivity of greater than or equal to 95%.

6. A manufacturing method of a circuit board is characterized by comprising the following steps:

7. The method for manufacturing a circuit board according to claim 6, wherein the steps of sequentially performing the processes of punching, metallization and image transfer on the double-sided board comprise:

forming a via hole penetrating through the double-sided board;

8. The method for manufacturing a wiring board according to claim 6, wherein the manufacturing of the first conductive traces comprises the steps of:

9. The method for manufacturing a wiring board according to claim 6, wherein before providing the light emitting unit, further comprising manufacturing a solder resist layer:

pre-baking the solder resist material;

and curing the solder resist material to obtain the solder resist layer.

10. The method for manufacturing a wiring board according to claim 9, further comprising the steps of: