Patent ID: 8079134
Filing Date: 2011-12-20
Classification: H01F,H01L,Y10T

Abstract:
1. A method for enhancing inductance of an on-chip inductance structure, said method comprising: depositing and patterning a magnetic bottom layer over a back-end-of-line metal layer or a finished portion of a chip; wherein said magnetic bottom layer forms a bottom portion of said on-chip inductance structure in a toroid configuration; creating a stacked multi-ring structure, said stacked multi-ring structure comprising: an input electrode, an output electrode, an output path, a center tap, and a plurality of open rings; wherein said plurality of open rings are vertically stacked on said chip; wherein each open ring of said plurality of open rings is constructed by a ring fabrication process, said ring fabrication process comprising: depositing an inter-ring spacer layer, removing portions of said inter-ring spacer layer to form a plurality of inter-ring spacer vias, filling said plurality of inter-ring spacer vias with an inter-ring connector material, and depositing and patterning a ring conductor film to form said each open ring over said inter-ring spacer layer and said inter-ring spacer vias, wherein said each open ring has a first end, a second end, and one or more gaps, wherein said first end is located at a first via of said plurality of inter-ring spacer vias, wherein if said each open ring is above a lowest open ring of said plurality of open rings, then a first portion of the inter-ring connector material in said first via connects said first end to a third end of a lower open ring of said plurality of open rings, wherein if said each open ring is said lowest open ring, then said first portion of the inter-ring connector material connects said first end to said input electrode, wherein a second portion of the inter-ring connector material in a second via of said plurality of inter-ring spacer vias forms a portion of said output path used for connecting to said output electrode, and wherein if said each open ring is a highest open ring of said plurality of open rings, then said second portion of the inter-ring connector material connects to said second end; wherein said center tap connects to a middle ring of said plurality of open rings; depositing a dielectric material; creating a plurality of toroid vias in said layer of dielectric material to expose portions of said magnetic bottom layer; wherein a central core via through center of said stacked multi-ring structure is one of said plurality of toroid vias; wherein one or more of said plurality of toroid vias is outside of said stacked multi-ring structure; filling said plurality of toroid vias with a magnetic material; wherein said filling step of filling the plurality of toroid vias comprises: depositing said magnetic material, and chemical-mechanical polishing of said magnetic material outside said plurality of toroid vias; wherein said magnetic material in said plurality of toroid vias and said stacked multi-ring structure form a middle portion of said on-chip inductance structure in said toroid configuration; and depositing and patterning a magnetic top layer over said dielectric material and said magnetic material in said plurality of toroid vias; wherein said magnetic top layer connects said magnetic material and forms a top portion of said on-chip inductance structure in said toroid configuration; and wherein each one of said magnetic material, said magnetic top layer, and said magnetic bottom layer is a type of fabrication magnetic material that comprises at least one of: Nickel, Ferrite, and a material with higher permeability than said dielectric material.