CN112492777B

CN112492777B - Circuit board and manufacturing method thereof

Info

Publication number: CN112492777B
Application number: CN201910866422.XA
Authority: CN
Inventors: 张鹏; 李彪; 侯宁; 李卫祥
Original assignee: Hongqisheng Precision Electronics Qinhuangdao Co Ltd; Avary Holding Shenzhen Co Ltd
Current assignee: Hongqisheng Precision Electronics Qinhuangdao Co Ltd; Avary Holding Shenzhen Co Ltd
Priority date: 2019-09-12
Filing date: 2019-09-12
Publication date: 2022-05-27
Anticipated expiration: 2039-09-12
Also published as: CN112492777A

Abstract

A manufacturing method of a circuit board comprises the following steps: providing a first substrate, wherein the first substrate comprises a first base layer, a first copper layer and a second copper layer, the first copper layer and the second copper layer are respectively formed on the first base layer, and the thickness of the first copper layer is larger than that of the second copper layer; etching the second copper layer to form a first circuit layer; providing a second substrate, and pressing the second substrate onto the first substrate; etching the first copper layer to form a heat dissipation layer; providing two third substrates, and respectively pressing the two third substrates onto the first substrate and the second substrate; providing a component, assembling the component on the heat dissipation layer, and electrically connecting with the third substrate; and covering the protective layers on two sides of the substrate, and removing the protective layers and the parts of the third substrate corresponding to the elements. The invention also provides a circuit board which is simple in structure and manufacturing process and can improve the heat dissipation effect.

Description

Circuit board and manufacturing method thereof

Technical Field

The invention relates to a circuit board and a manufacturing method thereof.

Background

In recent years, electronic products are widely used in daily work and life, and with the increasing functions of consumer electronic products, the power of electronic products is higher and higher, and the problem of heat dissipation of components in the electronic products is accompanied.

At present, the design of auxiliary components on a circuit board for heat dissipation is mainly an embedded copper block technology, however, the bonding force between the embedded copper block and the circuit board is insufficient, the board is easy to explode, and the flatness of the copper block and the circuit board is difficult to control.

Disclosure of Invention

Accordingly, there is a need for a circuit board and a method for fabricating the same that solve the above problems.

A manufacturing method of a circuit board comprises the following steps: providing a first substrate, wherein the first substrate comprises a first base layer and a first copper layer and a second copper layer which are respectively formed on the first base layer; etching the second copper layer to form a first circuit layer; providing a second substrate, and pressing the second substrate onto the first substrate; etching the first copper layer of the first substrate to form a heat dissipation layer at least comprising a heat dissipation pad; providing two third substrates, and respectively pressing the two third substrates onto the first substrate and the second substrate; covering a protective layer on the outer side of the third substrate, and removing part of the protective layer and part of the third substrate which are covered on the heat dissipation pad; and providing an element, assembling the element on the heat dissipation pad, and electrically connecting the element with the third substrate.

A circuit board, comprising: the substrate comprises a third substrate, a first substrate, a second substrate and another third substrate which are arranged in a stacking mode and electrically connected with each other, wherein the first substrate comprises a first base layer, a first circuit layer and a heat dissipation layer with a heat dissipation pad, wherein the first circuit layer and the heat dissipation layer are respectively formed on two opposite surfaces of the first base layer; a component assembled on the heat dissipation pad, the component being electrically connected to the third substrate; and the protective layer covers two sides of the substrate, and the positions of the protective layer and the third substrate corresponding to the elements are removed to expose the elements.

According to the circuit board with the heat dissipation structure, the elements are assembled on the heat dissipation layer of the substrate, copper blocks do not need to be embedded in the elements, the flatness of the circuit board is guaranteed, the heat dissipation layer and the base layer are tightly combined, and the manufacturing process is simple.

Drawings

Fig. 1 is a schematic cross-sectional view of a first substrate according to an embodiment of the invention.

FIG. 2 is a schematic cross-sectional view illustrating an etching process performed on the first substrate shown in FIG. 1.

Fig. 3 is a schematic cross-sectional view of a second substrate bonded to the first substrate shown in fig. 2.

FIG. 4 is a schematic cross-sectional view illustrating another etching process performed on the first substrate shown in FIG. 3.

Fig. 5 is a schematic cross-sectional view illustrating the first substrate and the second substrate shown in fig. 4 being laminated with a third substrate.

Fig. 6 is a schematic cross-sectional view illustrating an opening process performed on the substrate shown in fig. 5.

FIG. 7 is a schematic cross-sectional view of the substrate shown in FIG. 6 being subjected to an electroplating process.

Fig. 8 is a schematic cross-sectional view illustrating an etching process performed on the third substrate shown in fig. 7.

Fig. 9 is a schematic cross-sectional view of the protective layer covering the substrate shown in fig. 8.

Fig. 10 is a schematic cross-sectional view of a decap process performed on the substrate shown in fig. 9.

Fig. 11 is a schematic cross-sectional view of the substrate assembly device shown in fig. 10.

Description of the main elements

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

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Unless defined otherwise, 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 invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

Some embodiments of the invention are described in detail below with reference to the accompanying drawings. The embodiments described below and the features of the embodiments can be combined with each other without conflict.

Referring to fig. 1 to 11, a method for manufacturing a circuit board 100 with a heat dissipation function according to a first embodiment of the present invention includes the following steps:

step S1, please refer to fig. 1, a first substrate 10 is provided, in which the first substrate 10 includes a flexible first base layer 11, and a first copper layer 13 and a second copper layer 15 respectively formed on two opposite surfaces of the first base layer 11. The thickness of the first copper layer 13 is greater than the thickness of the second copper layer 15.

The material of the first base layer 11 may be selected from one of Polyimide (PI), Polypropylene (PI), Liquid Crystal Polymer (LCP), Polyetheretherketone (PEEK), Polyethylene Terephthalate (PET), and Polyethylene Naphthalate (PEN).

In the present embodiment, the thickness of the first base layer 11 is 12.5 to 25 μm, the thickness of the first copper layer 13 is 100 to 150 μm, and the thickness of the second copper layer 15 is 12 μm, but the present invention is not limited thereto.

In step S2, referring to fig. 2, a film pressing process, an exposing process, a developing process, an Etching process, and a film removing process (DES) are performed on the second copper layer 15, so that the second copper layer 15 forms a first circuit layer 151.

Step S3, please refer to fig. 3, in which a second substrate 20 and an adhesive layer 30 are provided, the second substrate 20 includes a flexible second base layer 21 and a second circuit layer 25 formed on a surface of the second base layer 21, and the second circuit layer 25 is laminated on the first circuit layer 151 through the adhesive layer 30. The adhesive layer 30 includes an inner layer 31 and outer layers 32 respectively formed on two opposite surfaces of the inner layer 31.

The second wiring layer 25 may be formed on the second base layer 21 by performing a lamination process, an exposure process, a development process, an Etching process, and a Stripping process (DES).

The material of the second base layer 21 and the inner layer 31 may be selected from one of Polyimide (PI), Polypropylene (PI), Liquid Crystal Polymer (LCP), Polyetheretherketone (PEEK), Polyethylene Terephthalate (PET), and Polyethylene Naphthalate (PEN).

In the present embodiment, the material of the outer layer 32 is thermoplastic polyimide, but is not limited thereto, and the material of the outer layer 32 may be at least one selected from polypropylene, epoxy resin, polyurethane, phenol resin, urea resin, melamine-formaldehyde resin, prepreg, and the like.

In step S4, referring to fig. 4, the first copper layer 13 is subjected to film pressing, exposing, developing, Etching, and de-molding (DES) processes, so that the first copper layer 13 forms the heat dissipation layer 131. The thermal dissipation layer 131 includes at least one thermal pad 1311.

Step S5, please refer to fig. 5, providing two third substrates 40, where the third substrate 40 includes a third base layer 41, and a third copper layer 43 and an adhesive layer 45 respectively formed on two opposite surfaces of the third base layer 41, the position of the adhesive layer 45 corresponding to the heat dissipation pad 1311 is cut and removed, and the two third substrates 40 are respectively bonded to the first substrate 10 and the second substrate 20.

Specifically, one of the third base layers 41 is laminated on the heat dissipation layer 131 through the corresponding adhesive layer 45, and the other third base layer 41 is laminated on the second base layer 21 through the corresponding adhesive layer 45.

In the present embodiment, the circuit board 100 is a rigid-flex board, and therefore, the two adhesive layers 45 are cut and removed corresponding to the position of the flexible board to be manufactured, but not limited to the rigid-flex board.

The third base layer 41 may be made of one material selected from FR-4 grade Polyimide (PI), Polypropylene (PP), Liquid Crystal Polymer (LCP), Polyetheretherketone (PEEK), Polyethylene Terephthalate (PET), and Polyethylene Naphthalate (PEN).

The material of the adhesive layer 45 may be at least one selected from polypropylene, epoxy resin, polyurethane, phenol resin, urea resin, melamine-formaldehyde resin, thermoplastic polyimide, prepreg, and the like.

In step S6, referring to fig. 6, a hole opening process is performed to open at least one through hole 50 along a stacking direction of the third substrate 40, the first substrate 10, the second substrate 20, and the other third substrate 40. The through hole 50 penetrates through the third substrate 40, the first substrate 10, the second substrate 20 and the other third substrate 40. At least one blind via 60 is formed along the stacking direction of the third copper layer 43, the third base layer 41, the adhesive layer 45 and the heat dissipation layer 131. The blind via 60 penetrates through the third copper layer 43, the third base layer 41, and the adhesive layer 45.

In the present embodiment, the through hole 50 and the blind hole 60 are formed by laser. In other embodiments, the through-hole 50 may be formed by other means, such as mechanical drilling, etc.

Step S7, please refer to fig. 7, in which an electroplating process is performed to form a conductive via 51 on the wall of the through hole 50, so that the first circuit layer 151, the second circuit layer 25 and the third copper layer 43 are electrically connected to each other; forming a conductive block 61 in the blind hole 60; plating layers 70 are formed on the surfaces of the two third copper layers 43, respectively.

In step S8, referring to fig. 8, a third circuit layer 431 is formed by performing a film pressing, exposing, developing, Etching, and Stripping (DES) process on the plating layer 70 and the third copper layer 43.

In step S9, referring to fig. 9, solder resists are printed on the third circuit layer 431, and the protective layer 80 is formed after exposure and development. The protective layer 80 fills the conductive hole 51 and covers the third circuit layer 431.

In the present embodiment, the protective layer 80 may be a solder mask (solder mask) or a cover layer (CVL) commonly used in the art.

Step S10, please refer to fig. 10, in which a cap opening process is performed to remove the protective layer 80, the plating layer 70 and the third substrate 40 covering the heat pads 1311, so as to expose the heat pads 1311; removing the protective layer 80 adjacent to both sides of the exposed thermal pad 1311 to expose the plating layer 70; the protective layer 80, the plating layer 70 and the third substrate 40 of the corresponding soft plate portion are removed.

In step S11, please refer to fig. 11, Surface Mount Technology (SMT) is performed, a component 90 is assembled on the thermal pad 1311 through an adhesive layer 91, and the component 90 and the exposed third circuit layer 431 are electrically connected through a wire 92.

Referring to fig. 11, an embodiment of the invention further provides a circuit board 100 with a heat dissipation structure, which includes a substrate, a protective layer 80 covering two sides of the substrate, and a component 90 assembled on the substrate. The substrate includes a heat dissipation layer 131, and the component 90 is bonded to the heat dissipation layer 131 and electrically connected to the substrate. The protective layer 80 is removed at the corresponding location of the element 90 to expose the element 90.

The substrate comprises a first substrate 10, a second substrate laminated on the first substrate 10 through a glue layer 30, and two third substrates 40 respectively laminated on the first substrate 10 and the second substrate 20. The first substrate 10 is electrically connected to the second substrate and the third substrate 40.

The first substrate 10 includes a first base layer 11, and a first circuit layer 151 and a heat dissipation layer 131 respectively formed on two opposite surfaces of the first base layer 11. The third substrate 40 corresponding to the component 90 is removed to expose the component 90.

The second substrate 20 includes a flexible second base layer 21 and a second circuit layer 25 formed on a surface of the second base layer 21.

The adhesive layer 30 includes an inner layer 31 and outer layers 32 respectively formed on two opposite surfaces of the inner layer 31. The material of the outer layer 32 is thermoplastic polyimide, but is not limited thereto. The second base layer 21 is pressed on the first circuit layer 151 through the glue layer 30.

The third substrate 40 includes a third base layer 41, and a third circuit layer 431 and an adhesive layer 45 respectively formed on two opposite surfaces of the third base layer 41, and the third base layer 41, the third copper layer 43 and the adhesive layer 45 are cut and removed at positions corresponding to the components 90. The third circuit layer 431 is electrically connected to the first circuit layer 151 and the second circuit layer 25 through a conductive via 51. The third circuit layer 431 is electrically connected to the heat dissipation layer 131 through the conductive bump 61.

The protective layer 80 fills the conductive hole 51 and covers the third circuit layer 431. The protective layer 80 is removed adjacent to both sides of the element 90, leaving the third circuit layer 431 exposed.

The element 90 is adhered to the heat dissipation layer 131 by an adhesive layer 91, and is electrically connected to the third circuit layer 431 by a wire 92.

The circuit board with the heat dissipation structure provided by the invention is not limited to a flexible circuit board, and can be a hard board, a rigid-flex board, a hybrid board, a ceramic board and the like. The circuit board provided by the invention is not limited to the four-layer board.

According to the circuit board 100 with the heat dissipation structure, the element 90 is assembled on the heat dissipation layer 131 of the substrate, a copper block does not need to be embedded, the flatness of the circuit board is guaranteed, the heat dissipation layer and the base layer are tightly combined, the overall structure of the circuit board is compact, and the manufacturing process is simple.

Although the present invention has been described with reference to the above preferred embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A manufacturing method of a circuit board comprises the following steps:

providing a first substrate, wherein the first substrate comprises a first base layer, a first copper layer and a second copper layer, the first copper layer and the second copper layer are respectively formed on the first base layer, the thickness of the first copper layer is 100-150 mu m, and the thickness of the second copper layer is 12 mu m;

etching the second copper layer to form a first circuit layer;

providing a second substrate, and pressing the second substrate onto the first substrate;

etching the first copper layer of the first substrate to form a heat dissipation layer at least comprising a heat dissipation pad;

providing two third substrates, and pressing the two third substrates onto the first substrate and the second substrate through two bonding layers respectively, wherein the region, corresponding to the heat dissipation pad, on one bonding layer is removed so that the heat dissipation pad is exposed outside the corresponding bonding layer;

covering a protective layer on the outer side of the third substrate, and removing part of the protective layer and part of the third substrate which are covered on the heat dissipation pad; and

and providing a component, assembling the component on the heat dissipation pad, and electrically connecting the component with the third substrate.

2. The method of claim 1, wherein electrically connecting the component to the third substrate is performed by removing the protective layer adjacent to both sides of the component to expose the third substrate; and electrically connecting the element with the third substrate through a lead.

3. The method of claim 1, wherein the step of providing a second substrate and bonding the second substrate to the first substrate comprises providing a second base layer and a second circuit layer formed on a surface of the second base layer, and bonding the second circuit layer to the first circuit layer through a glue layer.

4. The method for manufacturing a circuit board according to claim 3, wherein the step of providing the adhesive layer includes providing the adhesive layer including an inner layer and outer layers respectively formed on two opposite surfaces of the inner layer, and the outer layers are made of thermoplastic polyimide.

5. A circuit board, comprising:

the substrate comprises a third substrate, a first substrate, a second substrate and another third substrate which are arranged in a stacking mode and electrically connected with each other, the third substrate and the second substrate are respectively bonded with the first substrate through a bonding layer, the first substrate comprises a first base layer, a first circuit layer and a heat dissipation layer with a heat dissipation pad, the first circuit layer and the heat dissipation layer are respectively formed on two opposite surfaces of the first base layer, the thickness of the heat dissipation layer is 100-150 mu m, and the thickness of the first circuit layer is 12 mu m;

a component assembled on the heat dissipation pad, the component being electrically connected to the third substrate; and

and the protective layer covers two sides of the substrate, and the positions of the protective layer and the third substrate corresponding to the elements are removed to expose the elements.

6. The circuit board of claim 5, wherein the protective layer is removed proximate to both sides of the component to expose the third substrate, the component being electrically connected to the third substrate by a wire.

7. The circuit board of claim 6, wherein the second substrate comprises a second base layer and a second circuit layer formed on a surface of the second base layer, and the second circuit layer is laminated on the first circuit layer by an adhesive layer.

8. The circuit board of claim 7, wherein the adhesive layer comprises an inner layer and outer layers respectively formed on two opposite surfaces of the inner layer, and the outer layers are made of thermoplastic polyimide.