[0049] The circuit board and its manufacturing method provided by the technical solution will be described in further detail below in conjunction with the drawings and embodiments.
[0050] See figure 1 , The circuit board manufacturing method provided by the embodiment of the technical solution includes the steps:
[0051] The first step, see figure 2 , A copper-clad substrate 10 is provided. The copper-clad substrate 10 includes a base layer 11 and a copper foil layer 12 attached to the base layer 11.
[0052] 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 (PI), polyethylene terephthalate ( Polyethylene Terephthalate, PET), Teflon, Polyamide, Polymethylmethacrylate, Polycarbonate or Polyimide-Polyethylene-terephthalate Ester copolymer (Polyamide polyethylene-terephthalate copolymer) and so on. The copper foil layer 12 may be a rolled copper foil or an electrolytic copper foil. In this embodiment, the material of the base layer 11 is polyimide, and the copper foil layer 12 is rolled copper foil.
[0053] For the second step, please refer to image 3 with Figure 4 , The copper foil layer 12 is made into a circuit pattern 120. The method of forming the copper foil layer 12 into the circuit pattern 120 may be chemical etching or laser ablation. When the circuit pattern 120 is made by the chemical etching method, the parts of the copper foil layer 12 that do not need to be etched can be protected by the image transfer process first, so that the circuit composed of the remaining parts can be obtained after the copper foil layer 12 is chemically etched Graphic 120.
[0054] 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 spaced apart and substantially parallel to each other. 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 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 arranged in sequence.
[0055] The first circuit 121 includes a first connecting pad 1210 and a first wire 1211 connected to at least one side of the first connecting pad 1210. The first connecting pad 1210 is used for electrical connection with other components. The first wire 1211 Used to transmit electrical signals. The second circuit 122 includes a second connecting pad 1220 and a second wire 1221 connected to at least one side of the second connecting pad 1220. The second connecting pad 1220 is used for electrical connection with other components. The second wire 1221 Used to transmit electrical signals. The third circuit 123 includes a third connecting pad 1230 and a third wire 1231 connected to at least one side of the third connecting pad 1230. The third connecting pad 1230 is used for electrical connection with other components. 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 wire 1211 is connected to opposite sides of the first connection pad 1210, and the diameter of the first connection pad 1210 is larger than the line width of the first wire 1211. The second wire 1221 is connected to two 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. In addition, the first connecting pad 1210 corresponds to the second connecting pad 1220, and the third connecting pad 1230 corresponds to the fourth connecting pad 1240.
[0056] In this embodiment, image 3 Only a part of the five lines is shown as an illustration. Of course, those skilled in the art can understand that in the actual circuit board produced, the circuit pattern 120 may include more than five circuits, and the shape and distribution of the more than five circuits can be designed according to actual needs.
[0057] The third step, please refer to Figure 4 to 6 , A cover layer 13 is formed on the circuit pattern 120. The covering layer 13 can be formed by pressing a film, or can be formed by coating.
[0058] 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 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 at the central part is exposed to the first through hole 131, the second land 1220 at the central part is exposed to the second through hole 132, and the third land 1230 at the central part is exposed to the third through hole. Through hole 133, the fourth land 1240 in the central part 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 those of the first, second, third, and fourth lands 1210, 1220, 1230, and 1240, respectively diameter of. That is to say, except for the first land 1210 in the central part, the second land 1220 in the central part, the third land 1230 in the central part, and the fourth land 1240 in the central part, the covering layer 13 covers the rest The surface of the circuit pattern 120 and the part of the surface on the side where the copper foil layer 12 is attached to the base layer 11 is exposed from the circuit pattern 120.
[0059] For the fourth step, please refer to Figure 7 with Figure 8 , A conductive paste is printed on the cover layer 13 so that the conductive paste forms a connection structure 14 to be electrically connected to the circuit pattern 120.
[0060] The conductive paste may be copper conductive paste, silver conductive paste or other paste-like conductive materials with low resistivity, and generally includes resin, curing agent, and conductive powder mixed in the resin. Since the conductive paste is relatively viscous and has 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 cover 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 cover layer 13, it is also printed between the third through hole 133 and the fourth through hole 134 on the surface of the cover layer 13. That is, in this embodiment, the connection structure 14 includes a first conductive pillar 141 formed and filled in the first through hole 131, a second conductive pillar 142 filled in the second through hole 132, and a third through hole. The third conductive pillar 143 in 133, the fourth conductive pillar 144 filled in the fourth through hole 134, the first connection line 145 connecting the first conductive pillar 141 and the second conductive pillar 142 on the surface of the cover layer 13, and The second connecting line 146 on the surface of the covering layer 13 and connected to the third conductive pillar 143 and the fourth conductive pillar 144. The first connection line 145 and the second connection line 146 are substantially parallel, and the first connection line 145 and the first line 121 are substantially perpendicular. In this way, the first line 121 is electrically connected to the second line 122 through the first conductive pillar 141, the first connecting line 145 and the second conductive pillar 142, and the third line 123 is electrically connected to the second line 122 through the third conductive pillar 143 and the second connecting line 146. The fourth conductive pillar 144 is electrically connected to the fourth line 124.
[0061] In this embodiment, in order to ensure the reliability of the connection between the first conductive pillar 141 and the second conductive pillar 142, the surface of the first conductive pillar 141 exposed to the covering layer 13 is completely covered by the first connection line 145, and the second conductive pillar 142 The surface of the covering layer 13 exposed is also completely covered by the first connection line 145. That is, 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. 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 exposed to the covering layer 13 is completely covered by the second connecting line 146, and the fourth conductive pillar 144 exposes the covering layer 13 The surface is also completely covered by the second connection line 146. That is, 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.
[0062] The fifth step, please refer to Picture 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 protective layer 15 may be epoxy resin, PI, PET, Teflon, etc. In this embodiment, the protective layer 15 is made of insulating ink, which is formed on the surface of the first connection line 145 and the second connection line 146 by printing. The protective layer 15 fully covers the first connection line 145 and the second connection line 146, that is, neither the first connection line 145 nor the second connection line 146 is exposed to the outside.
[0063] Please refer to Figure 1 to Figure 9 The circuit board 100 manufactured by the above steps includes 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, a connecting structure 14 formed of conductive paste, and a covering connecting structure 14 Protection layer 15. 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 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 used for electrical connection with other components. 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 connecting pad 1210, a second through hole 132 corresponding to the second connecting pad 1220, and a third through hole 133 corresponding to the third connecting pad 1230. And a fourth through hole 134 corresponding to the fourth connection pad 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 143 filled in the third through hole 133 , The fourth conductive pillar 144 filled in the fourth through hole 134 is on the surface of the covering 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 to the first The second connection line 146 of the three conductive pillars 143 and the fourth conductive pillar 144. Thus, the first line 121 is electrically connected to the second line 122 through the first conductive pillar 141, the first connecting line 145, and the second conductive pillar 142, and the third line 123 is electrically connected to the second line 122 through the third conductive pillar 143 and the second connecting line 146. It is electrically connected to the fourth conductive pillar 144 and the fourth line 124. The protective layer 15 covers the surfaces 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 to prevent oxidation and affect the first line 121 and the second line The connection status of 122 and the connection status of the third line 123 and the fourth line 124.
[0064] 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 there are more lines to be connected in the line pattern 120, the connection structure 14 may include six or more conductive pillars and three or more connection lines, and these connection lines may be parallel, perpendicular or at an acute angle to each other. These connecting lines do not touch each other.
[0065] In the circuit board manufacturing method of the present technical solution, the connecting structure 14 is formed by opening holes in the covering layer 13 and filling the conductive paste, so that the lines of the circuit pattern 120 can be connected across the circuit, thus, in a simple and effective manner The method produces a circuit board 100 with a 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 cover layer is 60 microns, the thickness of the first connection line 145 is 18 microns, and the thickness of the protective layer 15 It is 12 microns, that is, the maximum thickness of the circuit board 100 is approximately 133 microns. The circuit board 100 has the advantages of being thin and light, and can be used in miniaturized electronic devices. Moreover, when the circuit board 100 is a soft board, it can have better flexural performance.
[0066] It is understandable that for those of ordinary skill in the art, various other corresponding changes and modifications can be made according to the technical concept of the present invention, and all these changes and modifications should fall within the protection scope of the claims of the present invention.
