Monolithic inductor with guard rings
First Claim
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1. A method of fabricating an inductor monolithically integrated in a semiconductor die, comprising:
- providing a semiconductor substrate;
forming a first layer of conductive material on the substrate;
patterning the first conductive layer to form a series of concentric rings;
forming a layer of insulating material on the substrate over the first conductive layer;
forming a second layer of conductive material on the substrate over the insulating layer;
patterning the second conductive layer to form a spiral conductor having successive turns generally superposed and overlying corresponding rings of the first conductive layer, so that at least one second layer turn overlies each first conductive layer ring; and
forming a unity gain voltage buffer on the substrate associated with at least one ring, said buffer having an output connected to the associated ring and an input connected to an overlying turn.
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Abstract
An integrated circuit and method of fabrication are disclosed for achieving electrical isolation between a spiral inductor and an underlying silicon substrate using standard semiconductor manufacturing process flow. A spiral conductor with square windings is formed in metal layer (20) patterned so that straight runs of successive turns (22, 23, 24) overlie corresponding runs of concentric square rings (16, 17, 18) formed in underlying metal layer (14). A unity gain voltage buffer (30) connects each ring (16, 17, 18) with a respective overlying turn (22, 23, 24).
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Citations
4 Claims
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1. A method of fabricating an inductor monolithically integrated in a semiconductor die, comprising:
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providing a semiconductor substrate;
forming a first layer of conductive material on the substrate;
patterning the first conductive layer to form a series of concentric rings;
forming a layer of insulating material on the substrate over the first conductive layer;
forming a second layer of conductive material on the substrate over the insulating layer;
patterning the second conductive layer to form a spiral conductor having successive turns generally superposed and overlying corresponding rings of the first conductive layer, so that at least one second layer turn overlies each first conductive layer ring; and
forming a unity gain voltage buffer on the substrate associated with at least one ring, said buffer having an output connected to the associated ring and an input connected to an overlying turn. - View Dependent Claims (2, 3, 4)
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Specification