Method of manufacturing a vertical inductor

A method of fabricating a spiral inductor, the method comprising:

• providing a substrate having a top surface and a bottom surface;
• forming a first set of through holes and a second set of through holes spaced apart from each other by a first distance, the through holes in the first set of the through holes and the through holes in the second set of through holes being spaced apart from each other by a second distance that is smaller than the first distance;
• forming a metal interconnect structure having at least one top metal layer on the top surface of the substrate, the metal interconnect structure configured to connect to a top portion of the through holes;
• and
• forming a redistribution layer having at least a bottom layer on the bottom surface of the substrate, the redistribution layer configured to connect to a bottom portion of the through holes to form a spiral structure in a same vertical plane.