Method for forming an inductor

Abstract

A spiral inductor fabricated above a semiconductor substrate provides a large inductance while occupying only a small surface area. Including a layer of magnetic material above and below the inductor increases the inductance of the inductor. The magnetic material also acts as barrier that confines electronic noise generated in the spiral inductor to the area occupied by the spiral inductor. Inductance in a pair of stacked spiral inductors is increased by including a layer of magnetic material between the stacked spiral inductors.

1 . A method of fabricating an inductor comprising:
 forming a magnetic material on a substrate;   forming an insulator of organic material on the magnetic material; and   forming an inductor pattern on the insulator.   
   
   
       2 . The method of  claim 1 , wherein
 forming the magnetic material comprises depositing a ferromagnetic material on the substrate, wherein the substrate is a silicon substrate;   forming the insulator comprises forming organic oxide material on the ferromagnetic material; and   forming the inductor pattern comprises forming a spiral octagon inductor pattern on the organic oxide material.   
   
   
       3 . The method of  claim 2 , further comprising:
 forming a second insulator of silicon dioxide on the spiral octagon inductor pattern; and   depositing magnetic oxide material on the second insulator.   
   
   
       4 . The method of  claim 1 , wherein
 forming the magnetic material comprises depositing magnetic oxide on the substrate,   forming the insulator comprises forming a polyimide material on the magnetic oxide material, and   forming the inductor pattern comprises forming a square polygonal spiral inductor pattern on the polyimide material.   
   
   
       5 . The method of  claim 4 , further comprising:
 depositing silicon dioxide on the square polygonal spiral inductor pattern; and   depositing a magnetic material on the silicon dioxide.   
   
   
       6 . The method of  claim 1 , wherein
 forming the magnetic material comprises depositing high permeability ferromagnetic material on a silicon substrate,   forming the insulator comprises forming a parylene material on the high permeability ferromagnetic material, and   forming the inductor pattern comprises forming a hexagonal spiral inductor pattern on the parylene material.   
   
   
       7 . The method of  claim 6 , further comprising:
 depositing silicon dioxide on the hexagonal spiral inductor pattern; and   depositing a nickel-iron material on the silicon dioxide.   
   
   
       8 . The method of  claim 1 , wherein
 forming the magnetic material comprises depositing ferromagnetic material on the substrate,   forming the insulator comprises forming a organic oxide material on the ferromagnetic material, and   forming an inductor pattern comprises forming a rectangular spiral inductor pattern on the organic oxide material.   
   
   
       9 . The method of  claim 8 , further comprising:
 depositing silicon dioxide on the rectangular spiral inductor pattern; and   depositing a nickel-iron material on the silicon dioxide.   
   
   
       10 . The method of  claim 1 , wherein
 forming the magnetic material comprises depositing magnetic material on the substrate, the substrate including silicon,   forming the insulator comprises forming an organic material on the magnetic material,   forming an inductor pattern comprises forming a spiral inductor pattern on the organic material, and   wherein the method further comprises:   depositing silicon dioxide on the spiral inductor pattern; and   depositing magnetic oxide material on the silicon dioxide.   
   
   
       11 . The method of  claim 10 , wherein the magnetic material comprises iron. 
   
   
       12 . The method of  claim 10 , wherein the spiral inductor pattern comprises gold. 
   
   
       13 . The method of  claim 1 , wherein
 forming the magnetic material comprises depositing magnetic oxide material on the substrate,   forming the insulator comprises depositing organic material on the magnetic oxide material,   forming the inductor pattern comprises forming a polygonal spiral inductor pattern on the organic material, and   wherein the method further comprises:   depositing silicon dioxide on the polygonal spiral inductor pattern; and   depositing an additional magnetic material on the silicon dioxide.   
   
   
       14 . The method of  claim 13 , wherein depositing the additional magnetic material on the silicon dioxide comprises depositing a nickel-iron alloy on the silicon dioxide. 
   
   
       15 . The method of  claim 13 , wherein the polygonal spiral inductor pattern comprises copper. 
   
   
       16 . The method of  claim 1 , wherein
 forming the magnetic material comprises depositing a high permeability ferromagnetic material on the substrate, the substrate including silicon   forming the insulator comprises depositing polyimide on the high permeability ferromagnetic material,   forming the inductor pattern comprises forming a triangular spiral inductor pattern on the polyimide material, and   wherein the method further comprises:   depositing silicon dioxide on the triangular spiral inductor pattern; and   depositing a nickel-iron alloy on the silicon dioxide.   
   
   
       17 . The method of  claim 16 , wherein depositing the nickel-iron alloy on the silicon dioxide comprises depositing an eighty-one percent nickel and about a nineteen percent iron nickel-iron alloy on the silicone dioxide. 
   
   
       18 . The method of  claim 1 , wherein
 forming the magnetic material comprises depositing a ferromagnetic material on the substrate,   forming the insulator comprises depositing parylene on the ferromagnetic material,   forming the inductor pattern comprises forming a square spiral inductor pattern on the parylene material, and   wherein the method further comprises:   depositing an oxide material on the square spiral inductor pattern; and   depositing iron on the oxide material.   
   
   
       19 . The method of  claim 18 , wherein
 depositing the oxide material comprises depositing an organic insulator material on the square spiral inductor pattern, and   the square spiral inductor pattern comprises copper.   
   
   
       20 . A method of fabricating an inductor comprising:
 depositing a first magnetic material on a substrate;   forming a first insulator of organic material on the first magnetic material;   forming an inductor pattern on the first insulator material wherein the inductor pattern comprises gold,   forming a second insulator on the inductor pattern; and   depositing a second magnetic material on the second insulator.   
   
   
       21 . The method of  claim 20 , wherein depositing at least one of the first and second magnetic materials comprises depositing a ferromagnetic material. 
   
   
       22 . The method of  claim 21 , wherein depositing the ferromagnetic material comprises depositing iron. 
   
   
       23 . The method of  claim 20  wherein forming the inductor pattern comprises forming a square spiral inductor pattern. 
   
   
       24 . The method of  claim 20 , wherein forming the inductor pattern includes forming a circular inductor pattern. 
   
   
       25 . The method of  claim 20 , wherein forming the inductor pattern includes forming a rectangular inductor pattern. 
   
   
       26 . The method of  claim 20 , wherein forming the inductor pattern includes forming a polygonal inductor pattern. 
   
   
       27 . The method of  claim 20 , wherein depositing at least one of the first and second magnetic material comprises depositing a nickel-iron alloy. 
   
   
       28 . The method of  claim 20 , wherein depositing at least one of the first and second magnetic material comprises depositing a nickel-iron alloy having a composition of about 81% nickel and 19% iron. 
   
   
       29 . The method of  claim 20 , wherein forming the first insulator comprises forming a polyimide material on the first magnetic material. 
   
   
       30 . The method of  claim 20 , wherein forming the first insulator comprises forming a parylene material on the first magnetic material. 
   
   
       31 . The method of  claim 20 , wherein the substrate comprises a silicon substrate. 
   
   
       32 . The method of  claim 20 , wherein the second insulator comprises silicone dioxide. 
   
   
       33 . The method of  claim 20 , wherein the substrate comprises a semiconductor material. 
   
   
       34 . A method of fabricating an inductor comprising:
 depositing a first magnetic material on a silicon substrate;   depositing a first insulating material on the first magnetic material;   forming an inductor pattern from gold on the first insulating material;   depositing a second insulating material on the inductor pattern; and   depositing a second magnetic material on the second insulating material.   
   
   
       35 . The method of  claim 35 , wherein the first magnetic material comprises a ferromagnetic material. 
   
   
       36 . The method of  claim 35 , wherein the ferromagnetic material comprises iron. 
   
   
       37 . The method of  claim 34 , wherein the inductor pattern comprises a square spiral pattern. 
   
   
       38 . The method of  claim 34 , wherein at least one of the first and second insulating materials comprises silicon dioxide. 
   
   
       39 . The method of  claim 34 , wherein at least one of the first and second insulating materials comprises polyimide. 
   
   
       40 . The method of  claim 34 , wherein the inductor pattern comprises a circular spiral pattern.