CN110650587A - Flexible circuit board and manufacturing method thereof - Google Patents

Flexible circuit board and manufacturing method thereof Download PDF

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Publication number
CN110650587A
CN110650587A CN201810669979.XA CN201810669979A CN110650587A CN 110650587 A CN110650587 A CN 110650587A CN 201810669979 A CN201810669979 A CN 201810669979A CN 110650587 A CN110650587 A CN 110650587A
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CN
China
Prior art keywords
copper
layer
circuit
clad
clad layer
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Pending
Application number
CN201810669979.XA
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Chinese (zh)
Inventor
刘立坤
李艳禄
魏豪毅
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Hongqisheng Precision Electronics Qinhuangdao Co Ltd
Avary Holding Shenzhen Co Ltd
Original Assignee
Hongqisheng Precision Electronics Qinhuangdao Co Ltd
Avary Holding Shenzhen Co Ltd
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Application filed by Hongqisheng Precision Electronics Qinhuangdao Co Ltd, Avary Holding Shenzhen Co Ltd filed Critical Hongqisheng Precision Electronics Qinhuangdao Co Ltd
Priority to CN201810669979.XA priority Critical patent/CN110650587A/en
Publication of CN110650587A publication Critical patent/CN110650587A/en
Pending legal-status Critical Current

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/02—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding
    • H05K3/022—Processes for manufacturing precursors of printed circuits, i.e. copper-clad substrates
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/0277—Bendability or stretchability details
    • H05K1/028—Bending or folding regions of flexible printed circuits
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/02—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding
    • H05K3/06—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding the conductive material being removed chemically or electrolytically, e.g. by photo-etch process

Abstract

A manufacturing method of a flexible circuit board comprises the following steps: providing a double-sided copper-clad substrate, wherein the double-sided copper-clad substrate comprises an insulating base layer and a first copper-clad layer formed on one surface of the base layer, and the double-sided copper-clad substrate comprises at least one power circuit area; plating copper on the surface of the first copper-clad layer far away from the base layer to form a copper-clad layer; etching and thinning other parts of the copper plating layer except for the part of the copper plating layer positioned in the power supply circuit area by using an exposure and development technology, wherein the part of the copper plating layer positioned in the power supply circuit area is reserved to form a copper reserving area; and etching the copper plating layer and the first copper-coated layer by using an exposure and development technology to obtain a first circuit layer, so as to obtain the flexible circuit board, wherein the first circuit layer comprises at least one power circuit positioned in the power circuit area, the power circuit comprises the copper-remaining area, and the thickness of the power circuit is greater than that of other circuits.

Description

Flexible circuit board and manufacturing method thereof
Technical Field
The invention relates to a flexible circuit board and a manufacturing method thereof.
Background
Electronic technology continues to advance toward technology refinement and product miniaturization. With the increasing of the I/O and power of the chip and the increasing requirements of the current full-screen and high-resolution screen on the power supply, the corresponding flexible circuit board is also subjected to the design requirement of high current. To meet the design requirement, it is usually necessary to add layers or increase the line width of the power source.
However, due to the requirements of electronic products for light weight and high density, the space for increasing the power line width of the flexible circuit board is reserved to be smaller. Moreover, the layer-adding of the flexible circuit board requires additional thermal processes such as pressing, baking, etc., which easily causes the reduction of the stability and precision of the flexible circuit board.
Disclosure of Invention
In view of the above, the present invention provides a flexible printed circuit and a method for manufacturing the same, which can solve the above problems.
The embodiment of the invention provides a manufacturing method of a flexible circuit board, which comprises the following steps: providing a double-sided copper-clad substrate, wherein the double-sided copper-clad substrate comprises an insulating base layer and a first copper-clad layer formed on one surface of the base layer, and the double-sided copper-clad substrate comprises at least one power circuit area; plating copper on the surface of the first copper-clad layer far away from the base layer to form a copper-clad layer; etching and thinning other parts of the copper plating layer except for the part of the copper plating layer positioned in the power supply circuit area by using an exposure and development technology, wherein the part of the copper plating layer positioned in the power supply circuit area is reserved to form a copper reserving area; and etching the copper plating layer and the first copper-coated layer by using an exposure and development technology to obtain a first circuit layer, so as to obtain the flexible circuit board, wherein the first circuit layer comprises at least one power circuit positioned in the power circuit area, the power circuit comprises the copper-remaining area, and the thickness of the power circuit is greater than that of other circuits.
An embodiment of the present invention further provides a flexible printed circuit, including: an insulating base layer; a first circuit layer formed on one surface of the base layer; the flexible circuit board comprises at least one power circuit area, the first circuit layer is manufactured by etching a first copper-clad layer and a copper-clad layer which are sequentially formed on one surface of the base layer, the other parts of the copper-clad layer except the part located in the power circuit area are etched, the part of the copper-clad layer located in the power circuit area is reserved to form a copper-remaining area, the first circuit layer comprises at least one power circuit located in the power circuit area, the power circuit comprises the copper-remaining area, and the thickness of the power circuit is larger than that of other circuits.
Compared with the prior art, the flexible circuit board is formed by two times of etching, the first time of etching is to thin the parts (local copper reduction) of the copper plating layer of the flexible circuit board, which are positioned in the fine circuit area and the common circuit area, and the part of the copper plating layer, which is positioned in the power circuit area, is reserved to form a copper reserving area; the second etching is to make the required conductive circuit (e.g., power circuit, fine circuit, etc.), and the copper-remaining region formed after the first etching is used to increase the thickness of the power circuit. So, can satisfy the demand to power supply line under the condition of not increasing power supply line width, avoid the thick restriction to the fine rule circuit of copper, increase the density of circuit to be favorable to the product to development to the direction of frivolous short and small.
Drawings
Fig. 1 is a schematic structural diagram of a double-sided copper-clad substrate according to a preferred embodiment of the invention.
Fig. 2 is a schematic structural view of the double-sided copper-clad substrate shown in fig. 1 after blind holes are formed therein.
Fig. 3 is a schematic structural view of the double-sided copper-clad substrate shown in fig. 2 after a conductive layer is formed thereon.
Fig. 4 is a schematic structural view of the structure shown in fig. 3 after a copper plating layer is formed on one of the conductive layers.
Fig. 5 is a schematic structural view of the copper-clad layer and the first copper-clad layer shown in fig. 4 covered with the first photosensitive layer and the second photosensitive layer, and subjected to exposure development.
Fig. 6 is a schematic structural view of the copper-plated layer shown in fig. 5 after etching.
Fig. 7 is a schematic structural diagram of the first photosensitive layer and the second photosensitive layer shown in fig. 6 after being removed.
Fig. 8 is a schematic view showing a structure in which the third photosensitive layer and the fourth photosensitive layer are coated on the copper-clad layer and the second copper-clad layer shown in fig. 7.
Fig. 9 is a schematic view showing the structure of the third photosensitive layer and the fourth photosensitive layer shown in fig. 8 after exposure and development.
Fig. 10 is a schematic structural diagram of the flexible printed circuit board obtained by etching the copper-clad layer, the first copper-clad layer and the second copper-clad layer shown in fig. 9 and removing the third photosensitive layer and the fourth photosensitive layer.
Description of the symbols
Figure BDA0001707863350000031
Figure BDA0001707863350000041
The following detailed description will further illustrate the invention in conjunction with the above-described figures.
Detailed Description
In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined object, the following detailed description is made on the specific embodiments, structures, features and effects of the method for manufacturing a flexible printed circuit board according to the present invention with reference to the accompanying drawings and preferred embodiments.
Referring to fig. 1 to 10, the present invention provides a method for manufacturing a flexible printed circuit 100. According to different requirements, the sequence of the steps of the manufacturing method of the flexible circuit board 100 can be changed, and some steps can be omitted or combined. The manufacturing method of the flexible circuit board 100 comprises the following steps:
referring to fig. 1, a double-sided copper-clad substrate 10 is provided. The double-sided copper-clad substrate 10 includes an insulating base layer 11, and a first copper-clad layer 12 and a second copper-clad layer 13 formed on two opposite surfaces of the base layer 11. The double-sided copper-clad substrate 10 is divided into at least one power line region 101, at least one fine line region 102 and at least one normal line region 103. The positional relationship among the power line region 101, the fine line region 102, and the normal line region 103 may be determined according to actual conditions.
The material of the base layer 11 may be selected from one of Polyimide (PI), Polyethylene Terephthalate (PET), Polyethylene naphthalate (PEN), and the like.
Referring to fig. 2, at least one blind via 14 is formed in the double-sided copper-clad substrate 10, and the blind via 14 penetrates through the first copper-clad layer 12 and the base layer 11. The bottom of the blind via 14 is closed by the second copper-clad layer 13.
In the present embodiment, the blind holes 14 are formed by laser drilling. The blind holes 14 are located in the normal wiring area 103.
Referring to fig. 3, a conductive layer 20 is formed on the surfaces of the first copper clad layer 12 and the second copper clad layer 13 away from the base layer 11, and the conductive layer 20 is further formed on the inner wall of the blind via 14, so as to form at least one via hole 15.
In the present embodiment, the conductive layer 20 is formed by a shadow method (shadow). Of course, in other embodiments, the conductive layer 20 may be omitted.
Step four, referring to fig. 4, copper is plated on the surface of the conductive layer 20, which is located on one side of the first copper-clad layer 12 and is away from the base layer 11, to form a copper-clad layer 30, and a portion of the copper-clad layer 30 is filled in the via hole 15 to form a conductive portion 31 for electrically connecting the first copper-clad layer 12, the copper-clad layer 30 and the second copper-clad layer 13.
Referring to fig. 5, a first photosensitive layer 40 and a second photosensitive layer 41 are respectively covered on the surfaces of the copper plating layer 30 and the second copper plating layer 13 away from the base layer 11, a required first patterned opening 42 is formed in the first photosensitive layer 40 by an exposure and development technique, and the first patterned opening 42 is used for exposing the copper plating layer 30 in the fine circuit area 102 and the normal circuit area 103.
The first photosensitive layer 40 and the second photosensitive layer 41 may be dry films.
Referring to fig. 6, the first photosensitive layer 40 with the first patterned opening 42 is used as a mask to etch and thin the copper plating layer 30 in the fine circuit area 102 and the normal circuit area 103. The copper plating layer 30 is covered by the first photosensitive layer 40 and is not etched, so that the copper plating layer 30 is remained in the power line region 101 to form a copper remaining region 32. Due to the copper-remaining region 32, the thinned copper plating layer 30 has a thickness in the power line region 101 that is greater than the thickness in the fine line region 102 and the thickness in the normal line region 103.
Wherein the second photosensitive layer 41 protects the second copper clad layer 13 from being etched during exposure and development.
In the present embodiment, the sum of the thicknesses of the first copper clad layer 12 and the thinned copper plated layer 30 in the fine line region 102 or the normal line region 103 is approximately 24 μm, and the thickness of the copper remaining region 32 is approximately 15 μm.
Step seven, please refer to fig. 7, the first photosensitive layer 40 and the second photosensitive layer 41 are removed.
Step eight, referring to fig. 8, a third photosensitive layer 50 and a fourth photosensitive layer 51 are respectively covered on the thinned copper plating layer 30 and the second copper plating layer 13.
In step nine, referring to fig. 9, a required second patterned opening 52 is formed in the third photosensitive layer 50 and the fourth photosensitive layer 51 by an exposure and development technique.
Step ten, referring to fig. 10, the third photosensitive layer 50 with the second patterned opening 52 is used as a mask to etch the copper plating layer 30, the conductive layer 20 and the first copper-clad layer 12 to obtain a first circuit layer 60, the fourth photosensitive layer 51 with the second patterned opening 52 is used as a mask to etch the conductive layer 20 and the second copper-clad layer 13 to obtain a second circuit layer 61, and then the third photosensitive layer 50 and the fourth photosensitive layer 51 are removed to obtain the flexible circuit board 100.
The first circuit layer 60 includes at least one power circuit 601 located in the power circuit region 101, at least one thin circuit 602 located in the thin circuit region 102, and at least one common circuit 603 located in the common circuit region 103. The power supply wiring 601 includes the copper-left region 32, and therefore, the thickness of the power supply wiring 601 is larger than the thickness of the fine wiring 602 and the thickness of the normal wiring 603.
Referring to fig. 10, a flexible circuit board 100 according to a preferred embodiment of the present invention is further provided, in which the flexible circuit board 100 includes an insulating base layer 11, and a first circuit layer 60 and a second circuit layer 61 formed on two opposite surfaces of the base layer 11. The flexible circuit board 100 is divided into at least one power line region 101, at least one fine line region 102, and at least one normal line region 103.
The first circuit layer 60 is formed by etching a first copper-clad layer 12 and a copper-clad layer 30 sequentially formed on one surface of the base layer 11. The second circuit layer 61 is formed by etching a second copper-clad layer 13 formed on the other surface of the base layer 11. Wherein, the copper plating layer 30 is etched in the fine circuit area 102 and the normal circuit area 103, and the copper plating layer 30 is remained in the power circuit area 101 to form a copper remained area 32. The first circuit layer 60 includes at least one power circuit 601 located in the power circuit region 101, at least one thin circuit 602 located in the thin circuit region 102, and at least one common circuit 603 located in the common circuit region 103. The power supply wiring 601 includes the copper-left region 32, and therefore, the thickness of the power supply wiring 601 is larger than the thickness of the fine wiring 602 and the thickness of the normal wiring 603.
The embodiment of the present invention forms the flexible wiring board 100 by etching twice. Wherein, the first etching is to thin the copper plating layer 30 of the flexible circuit board 100 in the fine circuit area 102 and the normal circuit area 103 (partially reducing copper), and the copper plating layer 30 in the power circuit area 101 is partially retained to form a copper retaining area 32; the second etching is to make the required conductive circuit (e.g., power circuit, fine circuit, etc.), and the copper-remaining region 32 formed after the first etching is used to increase the thickness of the power circuit 601. So, can satisfy the demand to power supply line under the condition of not increasing power supply line width, avoid the thick restriction to the fine rule circuit of copper, increase the density of circuit to be favorable to the product to development to the direction of frivolous short and small. Furthermore, compared to the process of plating the first copper-clad layer 12 locally and then plating the entire surface, the embodiment of the present invention can make the thickness of the copper-clad layer 30 in the power line region 101 more uniform, and can improve the limitation of the copper-plating thickness of the local plating technique.
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 (10)

1. A manufacturing method of a flexible circuit board comprises the following steps:
providing a double-sided copper-clad substrate, wherein the double-sided copper-clad substrate comprises an insulating base layer and a first copper-clad layer formed on one surface of the base layer, and the double-sided copper-clad substrate comprises at least one power circuit area;
plating copper on the surface of the first copper-clad layer far away from the base layer to form a copper-clad layer;
etching and thinning other parts of the copper plating layer except for the part of the copper plating layer positioned in the power supply circuit area by using an exposure and development technology, wherein the part of the copper plating layer positioned in the power supply circuit area is reserved to form a copper reserving area; and
and etching the copper plating layer and the first copper-coated layer by using an exposure and development technology to obtain a first circuit layer, so as to obtain the flexible circuit board, wherein the first circuit layer comprises at least one power circuit positioned in the power circuit area, the power circuit comprises the copper-remaining area, and the thickness of the power circuit is greater than that of other circuits.
2. The method of manufacturing a flexible wiring board according to claim 1, wherein the sum of the thicknesses of the first copper-clad layer and the thinned copper-clad layer except for the portion located in the power line region is 24 μm, and the thickness of the copper-remaining region is 15 μm.
3. The method of manufacturing a flexible wiring board according to claim 1, wherein the double-sided copper-clad substrate further includes a second copper-clad layer formed on the other surface of the base layer, and the method of manufacturing a flexible wiring board further includes:
at least one blind hole is formed in the double-sided copper-clad substrate, the blind hole penetrates through the first copper-clad layer and the base layer, and the bottom of the blind hole is sealed by the second copper-clad layer; and
and plating copper on the surface of the first copper-clad layer, which is far away from the base layer, to form a copper-clad layer, and filling part of the copper-clad layer in the blind hole to form a conductive part for electrically connecting the first copper-clad layer, the copper-clad layer and the second copper-clad layer.
4. The method of manufacturing a flexible wiring board according to claim 3, wherein before the copper plating layer is formed, the method of manufacturing a flexible wiring board further comprises:
forming a conducting layer on the surfaces, far away from the base layer, of the first copper-clad layer and the second copper-clad layer respectively, wherein the conducting layer is further formed on the inner wall of the blind hole, so that at least one conducting hole is formed;
the copper-clad layer is formed on the surface, far away from the base layer, of the conductive layer on one side of the first copper-clad layer, and the copper-clad layer is filled in the through hole to form the conductive part.
5. The method of manufacturing a flexible wiring board according to claim 3, further comprising:
and etching the second copper-clad layer by using an exposure and development technology to obtain a second circuit layer.
6. The method of manufacturing a flexible wiring board according to claim 3, wherein the blind holes are formed by laser drilling.
7. A flexible wiring board comprising:
an insulating base layer;
a first circuit layer formed on one surface of the base layer;
the flexible circuit board comprises at least one power circuit area, the first circuit layer is manufactured by etching a first copper-clad layer and a copper-clad layer which are sequentially formed on one surface of the base layer, the other parts of the copper-clad layer except the part located in the power circuit area are etched, the part of the copper-clad layer located in the power circuit area is reserved to form a copper-remaining area, the first circuit layer comprises at least one power circuit located in the power circuit area, the power circuit comprises the copper-remaining area, and the thickness of the power circuit is larger than that of other circuits.
8. The flexible wiring board of claim 7, wherein the sum of the thicknesses of the first copper-clad layer and the thinned copper-clad layer except for the portion located in the power line region is 24 μm, and the thickness of the copper-remaining region is 15 μm.
9. The flexible wiring board of claim 7, further comprising a second circuit layer formed on the other surface of said base layer.
10. The flexible printed circuit of claim 9, wherein at least one blind via is formed in the flexible printed circuit, the blind via penetrates through the first circuit layer and the base layer, the bottom of the blind via is sealed by the second circuit layer, and a portion of the first circuit layer is filled in the blind via to form a conductive portion for electrically connecting the first circuit layer and the second circuit layer.
CN201810669979.XA 2018-06-26 2018-06-26 Flexible circuit board and manufacturing method thereof Pending CN110650587A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114615813A (en) * 2022-03-12 2022-06-10 福建世卓电子科技有限公司 Production process of flexible circuit board with locally thin and thick circuit layer

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06268355A (en) * 1993-03-11 1994-09-22 Mitsubishi Electric Corp Printed wiring board and manufacture thereof
JPH06334311A (en) * 1993-05-18 1994-12-02 Yazaki Corp Manufacture of circuit body
CN103039131A (en) * 2010-08-03 2013-04-10 三井金属矿业株式会社 Method for producing printed wiring board, and printed wiring board

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06268355A (en) * 1993-03-11 1994-09-22 Mitsubishi Electric Corp Printed wiring board and manufacture thereof
JPH06334311A (en) * 1993-05-18 1994-12-02 Yazaki Corp Manufacture of circuit body
CN103039131A (en) * 2010-08-03 2013-04-10 三井金属矿业株式会社 Method for producing printed wiring board, and printed wiring board

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114615813A (en) * 2022-03-12 2022-06-10 福建世卓电子科技有限公司 Production process of flexible circuit board with locally thin and thick circuit layer
CN114615813B (en) * 2022-03-12 2023-12-15 福建世卓电子科技有限公司 Flexible circuit board production process with local thin and local thick circuit layers

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Application publication date: 20200103