| 摘要 |
A fabrication process of a conductive column suitable for a fabrication of a circuit board is provided. The circuit board comprises a dielectric layer. A first blind hole is formed in the dielectric layer from a first surface thereof, and a second blind hole is formed in the dielectric layer from a second surface opposite to the first surface, wherein the blind end of the first blind hole connects to the blind end of the second blind hole. The first blind hole and the second blind constitute a through hole and is formed in an hourglass shape such that an inner diameter of the through hole near to the first or the second surface is substantially larger than an inner diameter of the through hole near a middle portion of the through hole. A conductive material is filled in the through hole to form a conductive column.
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