Double-layer circuit board and manufacturing method thereof

Abstract

The invention discloses a double-layer circuit board and a manufacturing method therefor. The double-layer circuit board comprises a double-layer base material, and the upper surface of the double-layer base material is provided with a first circuit layer, and the lower surface of the double-layer base material is provided with a second circuit layer. The double-layer circuit board also comprises at least one conduction column which is covered by the double-layer base material. One end of the conduction column is disposed on the upper surface of the double-layer base material in an exposed manner, so as to electrically connect the second circuit layer. The other end of the conduction column is electrically connected with the first circuit layer. Because one end of the conduction column is disposed on the upper surface of the double-layer base material in the exposed manner, a part, corresponding to the conduction column, of the second circuit cannot generate a recess, so the yield of multilayer circuit boards is improved.

Description

technical field [0001] The invention relates to a double-layer circuit board and a manufacturing method thereof, in particular to a double-layer circuit board which is not easily formed by filling and plating holes and a manufacturing method thereof. Background technique [0002] see Figure 5 As shown, in the prior art double-layer circuit board, a first-layer circuit 301 and a second-layer circuit 302 are respectively formed on the upper and lower sides of the substrate 30, and the substrate has at least one through hole 303 penetrating the upper and lower sides of the substrate 30. , and the at least one through hole 303 is filled by electroplating to form a via column 304 to communicate and electrically connect the first-layer circuit 301 and the second-layer circuit 302 . [0003] see Figure 6 As shown, the manufacturing method of the existing double-layer circuit board includes the following steps: [0004] Such as Figure 6 As shown in (a), prepare a substrate 30 ...

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Problems solved by technology

[0012] see Figure 5 As shown, in the process of making the double-layer circuit board made by the prior art, especially in the step of electroplating the first electroplating layer 31, the at least one through hole 303 and the second electroplating layer 32, because electroplating forms at the same time The first layer of wiring 301, the second layer of wiring 302, and the via 304, and the via 304 is formed in the through hole 303, so when forming the via 304 must first fill the at least one through hole by electroplating 303 to form the conduction pillar 304, and at least one through hole 303 corresponding to the first layer circuit 301 and the second layer circuit 302 cannot be electroplated to form a thickness before the conduction pillar 304 is formed. After the column 304 is formed, the first layer of wiring 301 and the second layer of wiring 302 have been electroplated to a certain thickness, but the first layer of wiring 301 and the second layer of wiring 302 corresponding to the at least one through hole 304 has not been electroplated to a certain thickness.

Therefore, there will be a depression 305 at the place corresponding to the at least one conductive column 304 in the first layer circuit 301 and the second layer circuit 302, especially when the thickness of the substrate 30 is too large, resulting in the depth of the at least one through hole 303 being too deep When the first layer of wiring 301 and the second layer of wiring 302, the depression 305 will be quite obvious, and when the depression 305 is too deep, it will affect the first layer of wiring 301 and the second layer of wiring 302. Connection strength, thus affecting the yield of the double-layer circuit board

[0013] In addition, in the step of electroplating the first electroplating layer 31 , the at least one through hole 303 and the second electroplating layer 32 , when electroplating fills the at least one through hole 303 , due to the first layer of wiring 301 and the second layer of wiring 302 on both sides to fill the through hole 303 at the same time, so it is easy to fill the hole poorly and cause a gap 306 in the at least one through hole 303, the formation of the gap 306 will lead to the electrical connection of the first layer circuit 301 and the second layer circuit 302 Inadequate, and when the double-layer circuit board is in use, the temperature will rise, and the air in the gap 306 will expand when heated, but there is no way to vent it, resulting in an increase in pressure. If the temperature rises too much, it may cause the gap 306. The air pressure of the double-layer circuit board is too large, so that the double-layer circuit board bursts, which seriously affects the safety of use. Therefore, the double-layer circuit board made by the prior art needs to be further improved.

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