Inductor structure having embedded airgap

Abstract

Various embodiments include inductor structures including at least one air gap for reducing capacitance between windings in the inductor structure. One embodiment includes an inductor structure having: a substrate; an insulation layer overlying the substrate; a conductive winding overlying the substrate within the insulation layer, the conductive winding wrapped around itself to form a plurality of turns substantially concentric about a central axis; an insulating structural support containing an air gap between the conductive winding and the insulation layer, the insulating structural support at least one of under, over or surrounding the plurality of turns of the conductive winding or between adjacent turns in the conductive winding; and at least one insulation pocket located radially inside a radially innermost turn in the plurality of turns with respect to the central axis.

We claim: 
     
         1 . An inductor structure comprising:
 a substrate;   an insulation layer overlying the substrate;   a first conductive winding overlying the substrate within the insulation layer, the first conductive winding wrapped around itself to form a first plurality of turns substantially concentric about a central axis;   a second conductive winding overlying the first conductive winding within the insulation layer, the second conductive winding wrapped around itself to form a second plurality of turns substantially concentric about the central axis;   an insulating support structure containing an air gap between the second conductive winding and at least one of the insulation layer or the first conductive winding, the insulating support structure at least one of under, over or surrounding the plurality of turns of the second conductive winding or between adjacent turns in the second conductive winding; and   at least one insulation pocket located radially inside a radially innermost turn in the plurality of turns of the second conductive winding with respect to the central axis.   
     
     
         2 . The inductor structure of  claim 1 , wherein the at least one insulation pocket contains a second air gap. 
     
     
         3 . The inductor structure of  claim 1 , wherein the at least one insulation pocket includes a plurality of insulation pockets symmetrically dispersed about the central axis. 
     
     
         4 . The inductor structure of  claim 1 , wherein the air gap reduces a capacitance between adjacent turns in the plurality of turns in the second conductive winding. 
     
     
         5 . The inductor structure of  claim 1 , wherein each of the plurality of turns in the second conductive winding includes a set of substantially straight sections between each of a set of bends. 
     
     
         6 . The inductor structure of  claim 5 , wherein the insulating support structure containing the air gap spans approximately 45 percent to approximately 90 percent of a length of at least one of the substantially straight sections. 
     
     
         7 . The inductor structure of  claim 5 , wherein the insulating support structure containing the air gap spans approximately 66 percent to approximately 90 percent of a length of the at least one of the substantially straight sections. 
     
     
         8 . The inductor structure of  claim 5 , wherein the insulation pocket has a substantially trapezoidal shape with a first base having a first length and a second base have a second length greater than the first length, wherein the second length spans approximately 75 percent to approximately 85 percent of a length of the at least one of the substantially straight sections.