Manufacturing method of an inductive device

An inductive unit is formed in an integrated circuit. An electromagnetic radiation test is performed thereon. When an amount of electromagnetic radiation exceeds a radiation threshold value, a shielding structure is formed. The shielding structure has a width and a distance separated from the inductive unit such that a decreasing amount of a quality factor of the inductive unit is not larger than a first predetermined value and a shielded amount of electromagnetic radiation is not lower than a second predetermined value. The inductive unit has a symmetric shape and the inductive device further includes a single asymmetric inductive portion. The closed shape of the shielding structure encloses the inductive unit and covers the single asymmetric inductive portion. A part of the single asymmetric inductive portion extends along a peripheral direction of the shielding structure.