Three dimensional circuit including shielded inductor and method of forming same

An integrated circuit, comprising:

• a plurality of tiers including a first tier including a semiconductor substrate including a first active device layer formed therein and a second tier including a dielectric layer disposed above the first active device layer;
• a 3-D spiral inductor that traverses two or more of the plurality of tiers of the integrated circuit and includes a plurality of conductive lines formed above the dielectric layer, a plurality of conductive lines formed below the dielectric layer and a plurality of conductive vias extending vertically and coupling the plurality of conductive lines formed above the dielectric layer to the plurality of conductive lines formed below the dielectric layer;
• and
• a ground shield arranged laterally around at least a portion of the inductive element portion using at least two further conductive vias coupled to a ground and extending vertically from the first tier to the second tier.

A method of forming a three dimensional (3D) inductor, comprising:

• providing a first tier including at least one substrate having a first active device layer disposed at a surface of the at least one substrate;
• providing at least a second tier including a dielectric layer disposed above the first active device layer;
• forming a 3-D meandering type spiral inductor that traverses at least the first and second tiers and includes a plurality of conductive lines formed above the dielectric layer, a plurality of conductive lines formed below the dielectric layer and a plurality of vertically extending vias that couple the plurality of conductive lines formed above the dielectric layer to the plurality of conductive lines formed below the dielectric layer;
• and
• forming a ground shield cage using a top round ring formed from conductors disposed above the dielectric layer, a bottom round ring formed from conductors disposed below the dielectric layer, and additional conductive vias arranged laterally around the 3-D meandering type spiral inductor, each of the additional conductive vias extending from the top round ring to the bottom round ring and coupled to a ground.