CN102316681B - Circuit board and manufacturing method thereof - Google Patents

Abstract

The invention provides a circuit board manufacturing method, comprising the steps of: providing a copper-clad substrate, the copper-clad substrate includes a base layer and a copper foil layer; forming a circuit pattern on the copper foil layer, and the circuit pattern includes a first circuit and a second circuit; forming a covering layer on the circuit pattern, the covering layer has a first through hole and a second through hole, part of the first circuit is exposed in the first through hole, and part of the second circuit is exposed in the second through hole in; printing conductive paste on the covering layer, so that the conductive paste forms a first conductive column filled in the first through hole, a second conductive column filled in the second through hole, and connects the first conductive column and the second conductive column The first connection line of the two conductive columns, so that the first line is electrically connected to the second line through the first conductive column, the first connection line and the second conductive column; a protective layer is formed on the surface of the first connection line. The present invention also provides a circuit board made by the above-mentioned circuit board manufacturing method, which is light and thin.

Description

Circuit board and manufacturing method thereof

technical field

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

Background technique

In the information, communication and consumer electronics industries, circuit boards are an indispensable and basic component of all electronic information products. However, in portable electronic devices that require lightness, thinness, shortness, and smallness, such as mobile phones, it is necessary to use relatively thin and light circuit boards to realize circuit connections in a small space. With the improvement of people's requirements for portable electronic devices to process information, the lines on the circuit board are becoming more and more dense, and it is necessary for the lines to cross the cross-connect to realize the transmission and processing of electrical information. At this time, it is usually necessary to make the circuit board into a double-sided circuit board or a multi-layer circuit board to meet the connection requirements of the circuit. However, due to the relatively large thickness and weight of double-sided circuit boards or multi-layer circuit boards, it is difficult to meet the requirements of light weight and miniaturization of portable electronic devices.

Therefore, it is necessary to provide a thinner circuit board and a manufacturing method thereof.

Contents of the invention

A circuit board and its manufacturing method will be described below with an embodiment.

A method for manufacturing a circuit board, comprising the steps of: providing a copper-clad substrate, the copper-clad substrate including a base layer and a copper foil layer attached to the base layer; forming a circuit pattern on the copper foil layer, and the circuit pattern includes The first circuit and the second circuit; forming a covering layer on the circuit pattern, the covering layer has a first through hole and a second through hole, part of the first circuit is exposed in the first through hole, and part of the second circuit is exposed in the first through hole In the second through hole; print conductive paste on the cover layer, so that the conductive paste forms the first conductive column filled in the first through hole, the second conductive column filled in the second through hole and connects the first conductive column. The first connecting line of the column and the second conductive column, so that the first line is electrically connected to the second line through the first conductive column, the first connecting line and the second conductive column; a protective layer is formed on the surface of the first connecting line , to protect the first connecting line.

A circuit board, comprising a base layer, a circuit pattern formed on the surface of the base layer, a cover layer covering the circuit pattern, a connection structure formed by conductive paste and an insulating protective layer, the cover layer has a first through hole and a second a through hole, the connection structure includes a first conductive column filled in the first through hole, a second conductive column filled in the second through hole, and a first connection line connecting the first conductive column and the second conductive column, The first conductive column is in electrical contact with the first circuit, the second conductive column is in electrical contact with the second circuit, so that the first circuit is electrically connected with the second circuit, and the protective layer covers the first connection circuit , used to protect the first connecting line.

In the circuit board manufacturing method of this technical solution, by opening holes in the cover layer and filling the conductive paste, the lines of the circuit pattern can be cross-connected, so that a circuit board with a small thickness and a small volume can be produced . Moreover, when the manufactured circuit board is a flexible board, it can have better flexural performance and service life.

Description of drawings

FIG. 1 is a schematic flow chart of a method for manufacturing a circuit board provided by an embodiment of the technical solution.

FIG. 2 is a schematic cross-sectional view of a copper-clad substrate provided by an embodiment of the technical solution.

FIG. 3 is a schematic top view of forming a circuit pattern on the copper foil layer of the copper clad substrate in FIG. 2 .

FIG. 4 is a schematic cross-sectional view along line IV-IV of FIG. 2 .

FIG. 5 is a schematic diagram of forming a covering layer on the circuit pattern in FIG. 3 .

FIG. 6 is a schematic cross-sectional view along line VI-VI of FIG. 5 .

FIG. 7 is a schematic diagram of forming a connection structure on the cover layer of FIG. 5 .

FIG. 8 is a schematic cross-sectional view along line VIII-VIII of FIG. 7 .

FIG. 9 is a schematic diagram of forming a protective layer on the connection structure of FIG. 7 to make a circuit board.

Description of main component symbols

Copper Clad Substrates 10

Basal layer 11

Copper foil layer 12

Line Graphics 120

Line 1 121

Second Line 122

Third Route 123

Fourth Line 124

Fifth Route 125

The first connecting plate 1210

Lead wire 1211

The second connecting plate 1220

Second wire 1221

The third connecting plate 1230

Third wire 1231

The fourth connection plate 1240

Fourth wire 1241

Overlays 13

The first through hole 131

Second through hole 132

The third through hole 133

Fourth through hole 134

Connection Structure 14

The first conductive column 141

The second conductive column 142

The third conductive column 143

The fourth conductive column 144

The first connection line 145

Second connecting line 146

Protective layer 15

circuit board 100

Detailed ways

The circuit board provided by the technical solution and its manufacturing method will be further described in detail below in conjunction with the accompanying drawings and embodiments.

Please refer to Figure 1, the circuit board manufacturing method provided by the embodiment of the technical solution includes steps:

The first step, please refer to FIG. 2 , provides a copper clad substrate 10 , the copper clad substrate 10 includes a base layer 11 and a copper foil layer 12 attached to the base layer 11 .

In this embodiment, the copper clad substrate 10 is a single-layer copper foil substrate, that is, it only includes one copper foil layer 12 . The material of the base layer 11 can be a hard material, such as epoxy resin, glass fiber cloth, etc., or a flexible material, such as polyimide (Polyimide, PI), polyethylene terephthalate ( Polyethylene Terephthalate, PET), Teflon, Polyamide, Polymethylmethacrylate, Polycarbonate or Polyimide-polyethylene-terephthalate Ester copolymer (Polyamide polyethylene-terephthalatecopolymer), etc. The copper foil layer 12 may be rolled copper foil or electrolytic copper foil. In this embodiment, the base layer 11 is made of polyimide, and the copper foil layer 12 is rolled copper foil.

The second step, please refer to FIG. 3 and FIG. 4 , is to make the copper foil layer 12 into a circuit pattern 120 . The method of forming the copper foil layer 12 into the circuit pattern 120 can be chemical etching or laser ablation. When adopting the chemical etching method to make the circuit pattern 120, the part that does not need to be etched in the copper foil layer 12 can be protected by an image transfer process, so that the circuit formed by the remaining part can be obtained after the copper foil layer 12 is chemically etched Graphics120.

In this embodiment, the circuit pattern 120 includes a first circuit 121 , a second circuit 122 , a third circuit 123 , a fourth circuit 124 and a fifth circuit 125 that are spaced apart from each other and substantially parallel. The first line 121 is located between the third line 123 and the fifth line 125, the fifth line 125 is located between the first line 121 and the second line 122, and the second line is located between the fifth line 125 and the fifth line 125. between four lines 124 . That is to say, the third line 123 , the first line 121 , the fifth line 125 , the second line 122 and the fourth line 124 are arranged in sequence.

The first circuit 121 includes a first connection pad 1210 and a first wire 1211 connected to at least one side of the first connection pad 1210, the first connection pad 1210 is used for electrical connection with other components, and the first wire 1211 Used to transmit electrical signals. The second circuit 122 includes a second connection pad 1220 and a second wire 1221 connected to at least one side of the second connection pad 1220, the second connection pad 1220 is used for electrical connection with other components, and the second wire 1221 Used to transmit electrical signals. The third line 123 includes a third connection pad 1230 and a third wire 1231 connected to at least one side of the third connection pad 1230, the third connection pad 1230 is used for electrical connection with other components, and the third wire 1231 Used to transmit electrical signals. The fourth circuit 124 includes a fourth connection pad 1240 and a fourth wire 1241 connected to at least one side of the fourth connection pad 1240. The fourth connection pad 1240 is used for electrical connection with other components. The fourth wire 1241 Used to transmit electrical signals. In this embodiment, the first conductive wires 1211 are connected to opposite sides of the first connecting pad 1210 , and the diameter of the first connecting pad 1210 is greater than the line width of the first conductive wire 1211 . The second wire 1221 is connected to opposite sides of the second connection pad 1220 , and the diameter of the second connection pad 1220 is larger than the line width of the second circuit 122 . The third wire 1231 is connected to opposite sides of the third connection pad 1230 , and the diameter of the third connection pad 1230 is larger than the line width of the third wire 1231 . The fourth wire 1241 is also connected to opposite sides of the fourth connection pad 1240 , and the diameter of the fourth connection pad 1240 is larger than the line width of the fourth wire 1241 . Moreover, the first connection pad 1210 corresponds to the second connection pad 1220 , and the third connection pad 1230 corresponds to the fourth connection pad 1240 .

In this embodiment, only part of the five lines are shown in FIG. 3 for illustration. Certainly, those skilled in the art can understand that in an actual produced circuit board, the circuit pattern 120 may include more than five circuits, and the shape and distribution of more than five circuits may be designed according to actual needs.

The third step, please refer to FIGS. 4 to 6 together, is to form the covering layer 13 on the circuit pattern 120 . The covering layer 13 can be formed by lamination or by coating.

The cover layer 13 has a first through hole 131 , a second through hole 132 , a third through hole 133 and a fourth through hole 134 , the first land 1210 is fully or partially exposed to the first through hole 131 , the The second land 1220 is fully or partially exposed to the second through hole 132, the third land 1230 is fully or partially exposed to the third through hole 133, and the fourth land 1240 is fully or partially exposed to the fourth through hole. 134. In this embodiment, the first land 1210 of the central part is exposed to the first through hole 131, the second land 1220 of the central part is exposed to the second through hole 132, and the third land 1230 of the central part is exposed to the third through hole 132. Through hole 133 , the fourth land 1240 at the central portion is exposed to fourth through hole 134 . The diameters of the first through hole 131 , the second through hole 132 , the third through hole 133 and the fourth through hole 134 are respectively smaller than those of the first land 1210 , the second land 1220 , the third land 1230 and the fourth land 1240 diameter of. That is to say, except for the first land 1210 of the central part, the second land 1220 of the central part, the third land 1230 of the central part and the fourth land 1240 of the central part, the covering layer 13 covers the remaining lands. The surface of the circuit pattern 120 and the surface of the base layer 11 on the side where the copper foil layer 12 is pasted are exposed from the circuit pattern 120 .

The fourth step, please refer to FIG. 7 and FIG. 8 , is to print conductive paste on the covering layer 13 so that the conductive paste forms a connection structure 14 for electrical connection with the circuit pattern 120 .

The conductive paste can be copper conductive paste, silver conductive paste or other pasty conductive materials with low resistivity, generally including resin, curing agent and conductive powder mixed in the resin. Since the conductive paste is relatively viscous and has a certain fluidity, the conductive paste can be printed on a predetermined place by screen printing, so that a solid conductive material can be formed by curing the conductive paste. In this embodiment, when the conductive paste is printed on the covering layer 13, the conductive paste is fully filled in the first through hole 131, the second through hole 132, the third through hole 133 and the fourth through hole 134, and the printed Between the first through hole 131 and the second through hole 132 on the surface of the covering layer 13 , it is also printed between the third through hole 133 and the fourth through hole 134 on the surface of the covering layer 13 . That is to say, in this embodiment, the connection structure 14 includes a first conductive column 141 formed and filled in the first through hole 131, a second conductive column 142 filled in the second through hole 132, and a second conductive column 142 filled in the third through hole. The third conductive column 143 in 133, the fourth conductive column 144 filled in the fourth through hole 134, the first connection line 145 on the surface of the cover layer 13 and connecting the first conductive column 141 and the second conductive column 142, and The second connection line 146 is on the surface of the covering layer 13 and connects the third conductive pillar 143 and the fourth conductive pillar 144 . The first connection line 145 is substantially parallel to the second connection line 146 , and the first connection line 145 is substantially perpendicular to the first line 121 . In this way, the first circuit 121 is electrically connected to the second conductive column 142 and the second circuit 122 through the first conductive column 141, the first connecting circuit 145, and the third circuit 123 is electrically connected to the second circuit 122 through the third conductive column 143, the second connecting circuit 146 and The fourth conductive column 144 is electrically connected to the fourth line 124 .

In this embodiment, in order to ensure the connection reliability between the first conductive pillar 141 and the second conductive pillar 142, the surface of the first conductive pillar 141 exposed to the cover layer 13 is completely covered by the first connection line 145, and the second conductive pillar 142 The exposed surface of the covering layer 13 is also completely covered by the first connection lines 145 . That is to say, the length of the first connection line 145 is greater than or equal to the maximum distance between the first conductive pillar 141 and the second conductive pillar 142 . In order to ensure the reliability of the connection between the third conductive pillar 143 and the fourth conductive pillar 144, the surface of the third conductive pillar 143 that exposes the cover layer 13 is completely covered by the second connection line 146, and the fourth conductive pillar 144 exposes the surface of the cover layer 13. The surface is also completely covered by the second connecting line 146 . That is to say, the length of the second connection line 146 is greater than or equal to the maximum distance between the third conductive pillar 143 and the fourth conductive pillar 144 .

In the fifth step, referring to FIG. 9 , a protective layer 15 is formed on the surface of the first connection line 145 and the surface of the second connection line 146 to protect the first connection line 145 and the second connection line 146, so that the circuit board 100 can be obtained . The material of the protection layer 15 can be epoxy resin, PI, PET, Teflon, etc. In this embodiment, the protection layer 15 is insulating ink, which is formed on the surfaces of the first connecting circuit 145 and the second connecting circuit 146 by printing. The protective layer 15 fully covers the first connection lines 145 and the second connection lines 146 , that is, neither the first connection lines 145 nor the second connection lines 146 are exposed to the outside world.

Please refer to Fig. 1 to Fig. 9 together, the circuit board 100 that makes through the above steps comprises base layer 11, the circuit pattern 120 that is formed on the surface of base layer 11, the covering layer 13 that covers circuit pattern 120, the connection that is formed by conductive paste. structure 14 and a protective layer 15 covering the connection structure 14 . The line pattern 120 includes a first line 121 , a second line 122 , a third line 123 , a fourth line 124 and a fifth line 125 spaced apart from each other. The first circuit 121 has a first connection pad 1210 for electrical connection with other components, the second circuit 122 has a second connection pad 1220, and the second connection pad 1220 is also for electrical connection with other components, the The third line 123 has a third connection pad 1230 for electrical connection with other components, and the fourth line 124 has a fourth connection pad 1240 for electrical connection with other components. The covering layer 13 has a first through hole 131 corresponding to the first land 1210 , a second through hole 132 corresponding to the second land 1220 , and a third through hole 133 corresponding to the third land 1230 And the fourth through hole 134 corresponding to the fourth connection pad 1240 . The connection structure 14 includes a first conductive pillar 141 filled in the first through hole 131, a second conductive pillar 142 filled in the second through hole 132, and a third conductive pillar 143 filled in the third through hole 133. , the fourth conductive column 144 filled in the fourth through hole 134, the first connection line 145 on the surface of the cover layer 13 and connected to the first conductive column 141 and the second conductive column 142, and the surface of the cover layer 13 and connected to the first connection line 145 The third conductive pillar 143 and the second connection line 146 of the fourth conductive pillar 144 . Thus, the first circuit 121 is electrically connected to the second conductive column 142 and the second circuit 122 through the first conductive column 141, the first connecting circuit 145, and the third circuit 123 is passed through the third conductive column 143, the second connecting circuit 146 It is electrically connected with the fourth conductive column 144 and the fourth line 124 . The protective layer 15 is coated on the surface of the first connection line 145 and the second connection line 146, and is used to protect the first connection line 145 and the second connection line 146, and prevent its oxidation from affecting the first line 121 and the second line. 122, and the connection status of the third line 123 and the fourth line 124.

Of course, those skilled in the art can understand that when the lines in the line pattern 120 have other shapes and distributions, the connection structure 14 can be changed according to actual needs. When more circuits need to be connected in the circuit pattern 120, the connection structure 14 can include six or more conductive columns and three or more connection lines, and these connection lines can be parallel to each other, perpendicular or at an acute angle. It is sufficient that these connecting lines do not touch each other.

In the circuit board manufacturing method of the technical solution, the connection structure 14 is formed by opening holes in the cover layer 13 and filling the conductive paste, so that the lines of the line pattern 120 realize cross-over connections, so that the simple and effective The method produces a circuit board 100 with smaller thickness and better performance. Specifically, generally speaking, the thickness of the base layer 11 is 25 microns, the thickness of the copper foil layer 12 is 18 microns, the thickness of the covering layer is 60 microns, the thickness of the first connection line 145 is 18 microns, and the thickness of the protective layer 15 is is 12 microns, that is to say, the maximum thickness of the circuit board 100 is about 133 microns. The circuit board 100 has the advantage of being light and thin, and can be used in miniaturized electronic devices. Moreover, when the circuit board 100 is a flexible board, it can have better flexural performance.

It can be understood that those skilled in the art can make various other corresponding changes and modifications according to the technical concept of the present invention, and all these changes and modifications should belong to the protection scope of the claims of the present invention.

Claims (8)

1. a circuit board manufacturing method, comprises step:

A copper-clad base plate is provided, and described copper-clad base plate comprises basalis and fits in the copper foil layer of basalis;

Described copper foil layer is formed to line pattern, and described line pattern comprises the first circuit and the second circuit;

On line pattern, form cover layer, described cover layer has the first through hole and the second through hole, and part the first circuit is exposed in the first through hole, and part the second circuit is exposed in the second through hole;

Printing conductive cream on described cover layer, so that conductive paste forms the first conductive pole being filled in the first through hole, the first connection line that is filled in the second conductive pole in the second through hole and connects the first conductive pole and the second conductive pole, so that the first circuit is connected with the second line electricity with the second conductive pole by the first conductive pole, the first connection line, the length that adds and be less than or equal to described the first connection line of the diameter of the spacing of described the first conductive pole and the second conductive pole, the diameter of described the first conductive pole and described the second conductive pole; And

On described the first connection line surface, form protective layer, to protect the first connection line.

2. circuit board manufacturing method as claimed in claim 1, it is characterized in that, described line pattern also comprises tertiary circuit and the 4th circuit, and described the first circuit is between tertiary circuit and the 4th circuit, and described the second circuit is also between tertiary circuit and the 4th circuit; While forming cover layer on line pattern, described cover layer also has third through-hole and fourth hole, and part tertiary circuit is exposed in third through-hole, and part the 4th circuit is exposed in fourth hole; On described cover layer during printing conductive cream, also make conductive paste formation be filled in the 3rd conductive pole in third through-hole, the second connection line that is filled in the 4th conductive pole in fourth hole and connects the 3rd conductive pole and the 4th conductive pole, so that tertiary circuit is connected with the 4th line electricity with the 4th conductive pole by the 3rd conductive pole, the second connection line; Described protective layer is also formed on the second connection line surface.

3. circuit board manufacturing method as claimed in claim 1, it is characterized in that, described line pattern also comprises the 5th circuit between the first circuit and the second circuit, and the first circuit, the second circuit and the 5th circuit are parallel to each other, and described the first connection line is vertical with the first circuit.

4. circuit board manufacturing method as claimed in claim 1, it is characterized in that, the first wire that described the first circuit comprises the first terminal pad and is at least connected in the first terminal pad one side, described the first terminal pad is all or part of to be exposed in the first through hole, the second wire that described the second circuit comprises the second terminal pad and is at least connected in the second terminal pad one side, described the second terminal pad is all or part of to be exposed in the second through hole, the diameter of described the first terminal pad is greater than the live width of the first wire, and the diameter of described the second terminal pad is greater than the live width of the second wire.

5. a circuit board, comprise basalis, be formed at the line pattern on basalis surface and the cover layer that covers line pattern, described line pattern comprises the first circuit and the second circuit, it is characterized in that, described cover layer has the first through hole and the second through hole, described circuit board also comprises syndeton and protective layer, described syndeton is formed by conductive paste, and comprise the first conductive pole being filled in the first through hole, the first connection line that is filled in the second conductive pole in the second through hole and connects the first conductive pole and the second conductive pole, described the first conductive pole and the first circuit electrically contact, described the second conductive pole contacts with the second line electricity, thereby the first circuit is connected with the second line electricity, the spacing of described the first conductive pole and the second conductive pole, the length that adds and be less than or equal to described the first connection line of the diameter of the diameter of described the first conductive pole and described the second conductive pole, described protective layer is coated described the first connection line, for the protection of the first connection line.

6. circuit board as claimed in claim 5, is characterized in that, described line pattern also comprises tertiary circuit and the 4th circuit, and described the first circuit is between tertiary circuit and the 4th circuit, and described the second circuit is also between tertiary circuit and the 4th circuit; Described cover layer also has third through-hole and fourth hole, and part tertiary circuit is exposed in third through-hole, and part the 4th circuit is exposed in fourth hole; Described syndeton also comprises the 3rd conductive pole being filled in third through-hole, the second connection line that is filled in the 4th conductive pole in fourth hole and connects the 3rd conductive pole and the 4th conductive pole, so that tertiary circuit is connected with the 4th line electricity with the 4th conductive pole by the 3rd conductive pole, the second connection line; Described protective layer is also formed on the second connection line surface.

7. circuit board as claimed in claim 5, it is characterized in that, described line pattern also comprises the 5th circuit between the first circuit and the second circuit, and the first circuit, the second circuit and the 5th circuit are parallel to each other, and described the first connection line is vertical with the first circuit.

8. circuit board as claimed in claim 5, it is characterized in that, the first wire that described the first circuit comprises the first terminal pad and is at least connected in the first terminal pad one side, described the first terminal pad is all or part of to be exposed in the first through hole, the second wire that described the second circuit comprises the second terminal pad and is at least connected in the second terminal pad one side, described the second terminal pad is all or part of to be exposed in the second through hole, the diameter of described the first terminal pad is greater than the live width of the first wire, and the diameter of described the second terminal pad is greater than the live width of the second wire.

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