Patent ID: 7145428

Claim:
A circuit substrate, which has a first surface, a second surface corresponding to each other as well as a first micro-via and a second micro-via penetrating the first surface and the second surface, wherein the circuit substrate comprises: an inductor element, comprising: a first conductive column having a left conductive column and a right conductive column, which are separated from each other and are disposed in the first micro-via, the first conductive column forming a first upper portion on the first surface and forming a first lower portion on the second surface; a second conductive column, which is disposed in the second micro-via and adjacent to the first conductive column, forming a second upper portion on the first surface and forming a second lower portion on the second surface; a first trace, which is disposed on the second surface for electrically connecting with the first lower portion of the left conductive column of the first conductive column and the second lower portion of the second conductive column; a second trace, which is disposed on the first surface for electrically connecting with the first upper portion of the right conductive column of the first conductive column and the second upper portion of the second conductive column; and a reference plane, which is disposed on the second surface to make the magnetic line of force produced by the inductor element parallel to the reference plane.