TWI391053B - Printed circuit board and method for manufacturing the same - Google Patents

Description

Circuit board and manufacturing method thereof

The present invention relates to the field of circuit board technologies, and in particular, to a thinner and lighter circuit board and a method of fabricating the same.

In the information, communications and consumer electronics industries, circuit boards are an essential component of all electronic information products. In portable electronic devices with light, thin, short, and small requirements, such as mobile phones, thinner and thinner circuit boards are needed to achieve circuit connections in a small space. As the demand for processing information on portable electronic devices has increased, circuit boards have become increasingly dense, and lines have to be cross-connected for 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 realize the connection requirement of the line. However, since the double-sided circuit board or the multi-layer circuit board has a large thickness and weight, it is difficult to meet the requirements of lightweight and miniaturized portable electronic devices.

In view of this, it is necessary to provide a thinner and lighter circuit board and a method of fabricating the same.

A circuit board and a method of fabricating the same will be described below by way of embodiments.

A circuit board manufacturing method includes the steps of: providing a copper-clad substrate, the copper-clad substrate comprising a base layer and a copper foil layer adhered to the base layer; forming the copper foil layer into a circuit pattern, wherein the circuit pattern comprises Arranging a third line, a first line, a second line, and a fourth line, the first line comprising a first connecting plate and at least one side connected to the first connecting plate a first wire, the second wire includes a second land and a second wire connected to at least one side of the second land, the third wire includes a third land and at least one side connected to the third land a third wire, the fourth wire includes a fourth connecting plate and a fourth wire connected to at least one side of the fourth connecting plate, the diameter of the first connecting plate being larger than a line width of the first wire, the second connection The diameter of the disk is greater than the line width of the second wire, the diameter of the third land is greater than the line width of the third wire, the diameter of the fourth land is greater than the line width of the fourth wire; forming a cover layer on the line pattern The cover layer has a first through hole, a second through hole, a third through hole and a fourth through hole, wherein a central portion of the first lands is exposed in the first through hole, and a central portion of the second lands Exposing in the second through hole, the central portion of the third lands is exposed in the third through hole, the central portion of the fourth lands is exposed in the fourth through hole; and the conductive paste is printed on the cover layer, So that the conductive paste is formed to fill the first through hole a conductive pillar, a second conductive pillar filled in the second through hole, a third conductive pillar filled in the third through hole, a fourth conductive pillar filled in the fourth through hole, and the first conductive pillar and the second conductive pillar a first connecting line of the conductive post and a second connecting line connecting the third conductive post and the fourth conductive post, the first conductive post is in electrical contact with a central portion of the first lands, the second conductive post and the second a central portion of the lands electrically contacting, the third conductive post being in electrical contact with a central portion of the third lands, the fourth conductive post being in electrical contact with a central portion of the fourth lands, such that the first line is a conductive post, a first connecting line and a second conductive post are electrically connected to the second line and the third line is electrically connected to the fourth line by the third conductive post, the second connecting line and the fourth conductive post; wherein The first connection line is parallel to the second connection line; at the first connection line and the second connection line The surface forms a protective layer to protect the first connection line and the second connection line.

A circuit board comprising a base layer, a circuit pattern formed on a surface of the base layer, a cover layer covering the circuit pattern, a connection structure formed of a conductive paste, and a protective layer of insulation. The circuit pattern includes a third line, a first line, a second line, and a fourth line, which are sequentially arranged, the first line includes a first connecting plate and a first wire connected to at least one side of the first connecting plate, The second line includes a second lands and a second wire connected to at least one side of the second lands, the third line includes a third lands and a third wire connected to at least one side of the third lands. The fourth line includes a fourth connecting plate and a fourth wire connected to at least one side of the fourth connecting plate, the diameter of the first connecting plate is larger than the line width of the first wire, and the diameter of the second connecting plate is larger than the first wire The line width of the two wires is larger than the line width of the third wire, and the diameter of the fourth land is greater than the line width of the fourth wire. The cover layer has a first through hole, a second through hole, a third through hole and a fourth through hole, wherein a central portion of the first connecting plate is exposed in the first through hole, and a central portion of the second connecting plate is exposed In the second through hole, the central portion of the third lands is exposed in the third through hole, and the central portion of the fourth lands is exposed in the fourth through hole. The connection structure includes a first conductive pillar filled in the first through hole, a second conductive pillar filled in the second through hole, a third conductive pillar filled in the third through hole, and filled in the fourth through hole a fourth conductive pillar, a first connecting line connecting the first conductive pillar and the second conductive pillar, and a second connecting line connecting the third conductive pillar and the fourth conductive pillar, the first connecting line and the second connecting line The connection lines are parallel. The first conductive column and the first connection The central portion of the tray is in electrical contact, the second conductive post is in electrical contact with a central portion of the second lands, and the third conductive post is in electrical contact with a central portion of the third lands, the fourth conductive post and the The central portion of the four lands is in electrical contact such that the first line is electrically coupled to the second line and the third line is electrically coupled to the fourth line. The protective layer covers the first connecting line and the second connecting line for protecting the first connecting line and the second connecting line.

In the circuit board manufacturing method of the present technical solution, by forming a hole in the cover layer and filling the conductive paste, the circuit of the circuit pattern can be cross-connected, so that a circuit having a small thickness and a small volume can be formed. board. Moreover, when the manufactured circuit board is a soft board, it can have better flexing performance and service life.

The circuit board provided by the technical solution and the manufacturing method thereof are further described below with reference to the accompanying drawings and embodiments.

Referring to FIG. 1 , a circuit board manufacturing method provided by an embodiment of the present technical solution includes the following steps:

In the first step, referring to FIG. 2, a copper clad substrate 10 is provided. The copper clad substrate 10 includes a base layer 11 and a copper foil layer 12 adhered 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 a copper foil layer 12. The material of the base layer 11 may be a hard material such as an epoxy resin, a fiberglass cloth, or the like, or a flexible material such as Polyimide (PI) or polyethylene terephthalate ( Polyethylene Terephthalate, PET), PTFE (Teflon), Polyamide, Polymethylmethacrylate, Polycarbonate or Polyamide polyethylene-terephthalate copolymer Wait. The copper foil layer 12 may be a rolled copper foil or an electrolytic copper foil. In the present embodiment, the material of the base layer 11 is polyimide, and the copper foil layer 12 is a rolled copper foil.

In the second step, referring to FIG. 3 and FIG. 4, the copper foil layer 12 is formed into a wiring pattern 120. The method of forming the copper foil layer 12 into the wiring pattern 120 may be chemical etching or laser ablation. When the wiring pattern 120 is formed by a chemical etching method, the portion of the copper foil layer 12 that is not to be etched may be first protected by an image transfer process, so that the chemically etched copper foil layer 12 can be obtained by the remaining portion. The line graphic 120.

In the present embodiment, 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 that are spaced apart from each other and are 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 at the fifth line 125 and the second line Between four lines 124. That is, the third line 123, the first line 121, the fifth line 125, the second line 122, and the fourth line 124 are sequentially arranged.

The first line 121 includes a first lands 1210 and a first wire 1211 connected to at least one side of the first lands 1210. The first lands 1210 are for electrically connecting with other components, the first wire 1211 Used to transmit electrical signals. The second line 122 includes a second lands 1220 and is connected to the The second wire 1221 is connected to at least one side of the second disk 1220. The second wire 1220 is for electrically connecting with other components, and the second wire 1221 is for transmitting electrical signals. The third line 123 includes a third lands 1230 and a third wire 1231 connected to at least one side of the third lands 1230. The third lands 1230 are for electrically connecting with other components. The third wire 1231 Used to transmit electrical signals. The fourth line 124 includes a fourth lands 1240 and a fourth wire 1241 connected to at least one side of the fourth lands 1240. The fourth lands 1240 are for electrically connecting with other components. The fourth wire 1241 Used to transmit electrical signals. In this embodiment, the first wires 1211 are connected to opposite sides of the first lands 1210, and the diameter of the first lands 1210 is larger than the line width of the first wires 1211. The second wires 1221 are connected to opposite sides of the second lands 1220, and the diameter of the second lands 1220 is greater than the line width of the second line 122. The third wire 1231 is connected to opposite sides of the third land 1230, and the diameter of the third land 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 lands 1240, and the diameter of the fourth lands 1240 is greater than the line width of the fourth wire 1241. Also, the first lands 1210 correspond to the second lands 1220, and the third lands 1230 correspond to the fourth lands 1240.

In the present embodiment, only one of the five lines is illustrated in FIG. 3 as an illustration. Of course, those skilled in the art can understand that in the actually produced circuit board, the circuit pattern 120 can include more than five lines, and the shape and distribution of the five or more lines can be designed according to actual needs.

In the third step, referring to FIGS. 4 to 6, a cover layer 13 is formed on the line pattern 120. The cover layer 13 can be formed by laminating, or by Formed 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, and the first lands 1210 are all or partially exposed to the first through hole 131, The second lands 1220 are all or partially exposed to the second through holes 132, and the third lands 1230 are all or partially exposed to the third through holes 133, and the fourth lands 1240 are all or partially exposed to the fourth through holes. 134. In this embodiment, the first lands 1210 of the central portion are exposed to the first through holes 131, the second lands 1220 of the central portion are exposed to the second through holes 132, and the third lands 1230 of the central portion are exposed to the third The through hole 133, the fourth land of the central portion 1240 is exposed to the fourth through hole 134. The apertures of the first through hole 131, the second through hole 132, the third through hole 133, and the fourth through hole 134 are smaller than the first lands 1210, the second lands 1220, the third lands 1230, and the fourth lands 1240, respectively. The diameter. That is, the cover layer 13 covers the remaining lines except for the first lands 1210 of the central portion, the second lands 1220 of the central portion, the third lands 1230 of the central portion, and the fourth lands 1240 of the central portion. The surface of the pattern 120 and the portion of the surface of the base layer 11 to which the side of the copper foil layer 12 is exposed are exposed from the wiring pattern 120.

In the fourth step, referring to FIG. 7 and FIG. 8, the conductive paste is printed on the cover layer 13 so that the conductive paste forms the connection structure 14 to be electrically connected to the wiring pattern 120.

The conductive paste may be a copper conductive paste, a silver conductive paste or other paste conductive material having a low electrical resistivity, and generally includes a resin, a curing agent, and a conductive powder mixed in the resin. Since the conductive paste is relatively viscous and has a certain fluidity, the conductive paste can be printed at a predetermined position by screen printing. Thus, a solid conductive material can be formed by curing the conductive paste. In the embodiment, when the conductive paste is printed on the cover layer 13, the conductive paste is sufficiently filled in the first through hole 131, the second through hole 132, the third through hole 133, and the fourth through hole 134, and is printed. Between the first through hole 131 and the second through hole 132 on the surface of the cover layer 13, between the third through hole 133 and the fourth through hole 134 on the surface of the cover layer 13 is also printed. That is, in the present embodiment, the connection structure 14 includes a first conductive pillar 141 filled in the first through hole 131, and a second conductive pillar 142 filled in the second through hole 132 is filled in the third through hole 133. a third conductive pillar 146, a fourth conductive pillar 144 filled in the fourth through hole 134, a first connection line 145 on the surface of the cover layer 13 and connecting the first conductive pillar 141 and the second conductive pillar 142, and covered The surface of the layer 13 is connected to the third connecting line 143 of the third conductive pillar 146 and the fourth conductive pillar 144. The first connection line 145 is substantially parallel to the second connection line 143, and the first connection line 145 is substantially perpendicular to the first line 121. In this manner, the first line 121 is electrically connected to the second line 122 by the first conductive pillar 141, the first connecting line 145 and the second conductive pillar 142, and the third line 123 is connected by the third conductive pillar 146 and the second connecting line. The 143 and the fourth conductive pillar 144 are electrically connected to the fourth line 124.

In this embodiment, in order to ensure the connection reliability of the first conductive pillar 141 and the second conductive pillar 142, the surface of the first conductive pillar 141 exposing the cover layer 13 is completely covered by the first connecting line 145, and the second conductive pillar 142 The surface exposing the cover layer 13 is also completely covered by the first connection line 145. That is, the sum of the distance between the first conductive pillar 141 and the second conductive pillar 142, the diameter of the first conductive pillar 141, and the diameter of the second conductive pillar 142 is less than or equal to the length of the first connecting line 145. To ensure the third conductive pillar 146 and the fourth conductive pillar The connection reliability of 144, the surface of the third conductive pillar 146 exposing the cover layer 13 is all covered by the second connection line 143, and the surface of the fourth conductive pillar 144 exposing the cover layer 13 is also completely covered by the second connection line 143. That is, the length of the second connection line 143 is greater than or equal to the distance between the third conductive pillar 146 and the fourth conductive pillar 144. The sum of the distance between the third conductive pillar 146 and the fourth conductive pillar 144, the diameter of the third conductive pillar 146, and the diameter of the fourth conductive pillar 144 is less than or equal to the length of the second connecting line 143.

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 143 to protect the first connection line 145 and the second connection line 143, so that the circuit board 100 can be obtained. . The material of the protective layer 15 may be epoxy resin, PI, PET, Teflon, or the like. In this embodiment, the protective layer 15 is an insulating ink formed on the surface of the first connection line 145 and the second connection line 143 by printing. The protective layer 15 sufficiently covers the first connecting line 145 and the second connecting line 143, that is, neither the first connecting line 145 nor the second connecting line 143 are exposed to the outside.

Referring to FIG. 1 to FIG. 9 together, the circuit board 100 obtained by the above steps comprises a base layer 11, a circuit pattern 120 formed on the surface of the base layer 11, a cover layer 13 covering the circuit pattern 120, and a conductive paste. The connection structure 14 and the 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 that are spaced apart from each other. The first line 121 has a first lands 1210 for electrical connection with other components, the second line 122 has a second lands 1220, and the second lands 1220 are also used for electrical connection with other components. The third line 123 has been used for other components A third lands 1230 are electrically connected, the fourth line 124 having a fourth lands 1240 for electrical connection with other components. The cover layer 13 has a first through hole 131 corresponding to the first connecting plate 1210, a second through hole 132 corresponding to the second connecting plate 1220, and a third through hole 133 corresponding to the third connecting plate 1230. And a fourth through hole 134 corresponding to the fourth lands 1240. The connecting 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 146 filled in the third through hole 133 . a fourth conductive pillar 144 filled in the fourth through hole 134, on the surface of the cover layer 13 and connected to the first connecting line 145 of the first conductive pillar 141 and the second conductive pillar 142, and on the surface of the covering layer 13 and connected The third conductive pillar 146 is connected to the second connecting line 143 of the fourth conductive pillar 144. The first line 121 is electrically connected to the second line 122 by the first conductive pillar 141, the first connecting line 145 and the second conductive pillar 142, and the third line 123 is connected by the third conductive pillar 146 and the second connection. Line 143 and fourth conductive post 144 are electrically coupled to fourth line 124. The protective layer 15 is coated on the surfaces of the first connecting line 145 and the second connecting line 143 for protecting the first connecting line 145 and the second connecting line 143 from oxidation and affecting the first line 121 and the second line. The connection state of 122, and the connection state 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 lines in the line pattern 120 need to be connected, the connection structure 14 may include six or more conductive columns and three or more connection lines, and the connection lines may be parallel, perpendicular or Sharp angles only need to be in contact with each other.

In the circuit board manufacturing method of the present invention, the connection structure 14 is formed by opening the hole in the cover layer 13 and filling the conductive paste, so that the line of the line pattern 120 realizes the cross-cross connection, so that it is simple and effective. The method produces a circuit board 100 having a small thickness and good performance. Specifically, in general, the thickness of the base layer 11 is 25 micrometers, the thickness of the copper foil layer 12 is 18 micrometers, the thickness of the cover layer is 60 micrometers, the thickness of the first connection line 145 is 18 micrometers, and the thickness of the protective layer 15 It is 12 microns, that is, the maximum thickness of the board 100 is approximately 133 microns. The circuit board 100 has the advantage of being thin and light, and can be used in a miniaturized electronic device. Moreover, when the circuit board 100 is a soft board, it can have better flexing performance.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

10‧‧‧Copper-clad substrate

11‧‧‧ basal layer

12‧‧‧copper layer

120‧‧‧Line graphics

121‧‧‧First line

122‧‧‧second line

123‧‧‧ third line

124‧‧‧fourth line

125‧‧‧ fifth line

1210‧‧‧First connection disk

1211‧‧‧First wire

1220‧‧‧Second connection plate

1221‧‧‧second wire

1230‧‧‧ Third connection plate

1231‧‧‧ Third wire

1240‧‧‧4th connection plate

1241‧‧‧fourth wire

13‧‧‧ Coverage

131‧‧‧First through hole

132‧‧‧Second through hole

133‧‧‧ third through hole

134‧‧‧fourth through hole

14‧‧‧ Connection structure

141‧‧‧First conductive column

142‧‧‧Second conductive column

146‧‧‧The third conductive column

144‧‧‧fourth conductive column

145‧‧‧First connection line

143‧‧‧Second connection line

15‧‧‧Protective layer

100‧‧‧ boards

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

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

3 is a schematic plan view showing a copper foil layer of the copper-clad substrate of FIG. 2 in a line pattern.

Figure 4 is a cross-sectional view taken along line IV-IV of Figure 2.

Figure 5 is a schematic view showing the formation of a cover layer on the line pattern of Figure 3.

Figure 6 is a cross-sectional view taken along line VI-VI of Figure 5.

Figure 7 is a schematic view showing the formation of a joint structure on the cover layer of Figure 5.

Figure 8 is a cross-sectional view taken along line VIII-VIII of Figure 7.

Figure 9 is a schematic view showing the formation of a protective layer on the connection structure of Figure 7 to form a circuit board.

100‧‧‧ boards

11‧‧‧ basal layer

13‧‧‧ Coverage

121‧‧‧First line

122‧‧‧second line

141‧‧‧First conductive column

142‧‧‧Second conductive column

145‧‧‧First connection line

15‧‧‧Protective layer

Claims (6)

A circuit board manufacturing method includes the steps of: providing a copper-clad substrate, the copper-clad substrate comprising a base layer and a copper foil layer adhered to the base layer; forming the copper foil layer into a circuit pattern, wherein the circuit pattern comprises Arranging a third line, a first line, a second line, and a fourth line, the first line comprising a first lands and a first wire connected to at least one side of the first lands, the second line comprising a second connecting wire and a second wire connected to at least one side of the second connecting plate, the third line comprising a third connecting plate and a third wire connected to at least one side of the third connecting plate, the fourth line comprising a fourth connecting plate and a fourth wire connected to at least one side of the fourth connecting plate, wherein the diameter of the first connecting plate is larger than the line width of the first wire, and the diameter of the second connecting plate is larger than the line width of the second wire; The diameter of the third lands is greater than the line width of the third wire, the diameter of the fourth lands is greater than the line width of the fourth wire; a cover layer is formed on the line pattern, the cover layer has a first through hole, Second through hole, a third through hole and a fourth through hole, wherein a central portion of the first lands is exposed in the first through hole, a central portion of the second lands is exposed in the second through hole, and a central portion of the third lands is exposed In the third through hole, the central portion of the fourth lands is exposed in the fourth through hole; and the conductive paste is printed on the cover layer to form the conductive paste to form the first conductive pillar filled in the first through hole a second conductive pillar filled in the second through hole, a third conductive pillar filled in the third through hole, a fourth conductive pillar filled in the fourth through hole, and the first conductive pillar and the second conductive pillar a first connecting line and a second connecting line connecting the third conductive post and the fourth conductive post, The first conductive post is in electrical contact with a central portion of the first lands, the second conductive post is in electrical contact with a central portion of the second lands, and the third conductive post is in electrical contact with a central portion of the third lands. The fourth conductive post is in electrical contact with the central portion of the fourth land such that the first line is electrically connected to the second line by the first conductive post, the first connecting line and the second conductive post, and the third line is borrowed Electrically connecting from the third conductive post, the second connecting line and the fourth conductive post to the fourth line; wherein the first connecting line is parallel to the second connecting line; and in the first connecting line and the second A protective layer is formed on the surface of the connection line to protect the first connection line and the second connection line. The circuit board manufacturing method according to claim 1, wherein the circuit pattern further includes a fifth line between the first line and the second line, and the first line, the second line, and the fifth line are mutually Parallel, the first connection line is perpendicular to the first line. The method for fabricating a circuit board according to claim 1, wherein a distance between the first conductive pillar and the second conductive pillar, a diameter of the first conductive pillar, and a diameter of the second conductive pillar are added. And less than or equal to the length of the first connection line. A circuit board comprising: a base layer; a line pattern formed on a surface of the base layer, the line pattern comprising a third line, a first line, a second line, and a fourth line arranged in sequence, the first The circuit includes a first lands and a first wire connected to at least one side of the first lands, the second line includes a second lands and a second wire connected to at least one side of the second lands, the third The line includes a third lands and a third guide connected to at least one side of the third lands a fourth line comprising a fourth connecting plate and a fourth wire connected to at least one side of the fourth connecting plate, wherein the diameter of the first connecting plate is larger than a line width of the first connecting wire, and the second connecting plate The diameter of the third connecting plate is larger than the line width of the third wire, the diameter of the fourth connecting plate is larger than the line width of the fourth wire; the cover layer, the cover layer covers the line Graphically, the cover layer has a first through hole, a second through hole, a third through hole and a fourth through hole, wherein a central portion of the first lands is exposed in the first through hole, and a center of the second lands Partially exposed in the second through hole, the central portion of the third lands is exposed in the third through hole, the central portion of the fourth lands is exposed in the fourth through hole; and the connecting structure is electrically conductive The paste is formed, and includes a first conductive pillar filled in the first through hole, a second conductive pillar filled in the second through hole, a third conductive pillar filled in the third through hole, and filled in the fourth through hole a fourth conductive column, connecting the first conductive column and the second conductive column a connection line and a second connection line connecting the third conductive column and the fourth conductive column, the first connection line is parallel to the second connection line, and the first conductive column and the central portion of the first connection plate are electrically Contacting, the second conductive post is in electrical contact with a central portion of the second lands, the third conductive post is in electrical contact with a central portion of the third lands, the central portion of the fourth conductive post and the fourth lands Electrically contacting, such that the first line is electrically connected to the second line, and the third line is electrically connected to the fourth line; and the protective layer covers the first connecting line and the second connecting line for protection The first connection line and the second connection line. The circuit board of claim 4, wherein the circuit pattern further comprises a fifth line between the first line and the second line, the first line, the second line and the fifth line being parallel to each other, The first connection line Vertical to the first line. The circuit board of claim 4, wherein a distance between the first conductive pillar and the second conductive pillar, a diameter of the first conductive pillar, and a diameter of the second conductive pillar are less than Or equal to the length of the first connection line.