Method for forming an inductor in a ceramic substrate
A method for making an embedded toroidal inductor ( 118 ) includes forming in a ceramic substrate ( 100 ) a first plurality of conductive vias ( 102 ) radially spaced a first distance from a central axis ( 101 ) so as to define an inner circumference. A second plurality of conductive vias ( 104 ) is formed radially spaced a second distance about the central axis so as to define an outer circumference. A first plurality of conductive traces ( 110 ) forming an electrical connection between substantially adjacent ones of the first and second plurality of conductive vias is formed on a first surface ( 106 ) of the ceramic substrate. Further, a second plurality of conductive traces ( 110 ) forming an electrical connection between circumferentially offset ones of the first and second plurality of conductive vias is formed on a second surface of the ceramic substrate opposed from the first surface to define a three dimensional toroidal coil.
1. A method for forming an inductor in a ceramic substrate, comprising the steps of:
forming a conductive coil comprising a plurality of turns about an unfired ceramic toroidal core region defined within an unfired ceramic substrate;
co-firing said ceramic toroidal core region, said ceramic substrate, and said conductive coil to form an integral ceramic substrate structure with said conductive coil at least partially disposed within the integral ceramic substrate structure; and
disposing a conductive ground plane layer between said conductive coil and an outer surface of said integral ceramic substrate structure.
2. The method according to claim 1 , further comprising the step of forming said ceramic toroidal core region of a ceramic material having a permeability greater than one.
3. The method according to claim 1 further comprising the step of forming said conductive coil with a plurality of winding layers, each winding layer defining a toroidal coil disposed about said ceramic toroidal core and having a coil radius different from an adjacent winding layer.
4. The method according to claim 1 , wherein said disposing further comprises configuring said conductive ground plane layer to be electrically isolated from said conductive coil.