Patent ID: 8354325
Filing Date: 2013-01-15
Classification: H01L

Abstract:
1. A method for forming a toroidal inductor, the method comprising: forming a first plurality of conductive vias in a top surface of a semiconductor layer and a second plurality of conductive vias in the top surface of the semiconductor layer, wherein the first plurality of conductive vias is formed in a first circular pattern in the semiconductor layer and the second plurality of conductive vias is formed in a second circular pattern in the semiconductor layer, wherein the second circular pattern surrounds the first circular pattern, and wherein each of the first and second plurality of conductive vias extend into the semiconductor layer from the top surface towards a bottom surface of the semiconductor layer, opposite the top surface, and wherein each of the second plurality of conductive vias has a length along the top surface of the semiconductor layer that is longer than a length of each of the first plurality of conductive vias along the top surface of the semiconductor layer; forming a first patterned conductive layer over the top surface of the semiconductor layer and over the first and second plurality of conductive vias, wherein the first patterned conductive layer has a first plurality of conductive portions, each conductive portion of the first plurality of conductive portions being in contact with a corresponding conductive via of the first plurality of conductive vias and a corresponding conductive via of the second plurality of conductive vias; removing a portion of the semiconductor layer from the bottom surface of the semiconductor layer to expose each of the first and second plurality of conductive vias at the bottom surface of the semiconductor layer; and forming a second patterned conductive layer over the bottom surface of the semiconductor layer and over the first and second plurality of conductive vias at the bottom surface of the semiconductor layer, wherein the semiconductor layer and the first and second plurality of conductive vias are between the first patterned conductive layer and the second patterned conductive layer, wherein the second patterned conductive layer has a second plurality of conductive portions, each conductive portion of the second plurality of conductive portions being in contact with a corresponding conductive via of the first plurality of conductive vias and a corresponding conductive via of the second plurality of conductive vias, wherein the first patterned conductive layer, the first plurality of conductive vias, the second plurality of conductive vias, and the second patterned conductive layer form a toroidal inductor coil.