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US 8,525,281 B2Granted
Z-axis semiconductor fluxgate magnetometer
AssigneeTexas Instruments Incorporated
InventorsAnuraag Mohan, Peter J. Hopper
Life of this patent
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Abstract
A z-axis fluxgate magnetometer is formed in a semiconductor wafer fabrication sequence, which significantly reduces the size and cost of the fluxgate magnetometer. The semiconductor wafer fabrication sequence forms a vertical magnetic core structure, a first wire structure wound around the magnetic core structure, and a second wire structure wound around the magnetic core structure.
Claims9
A z-axis semiconductor fluxgate magnetometer comprising:
- a Semiconductor structure, having a bottom surface, a top surface and a cavity extending from the semiconductor top surface down into the semiconductor structure, wherein the cavity has a side wall surface and a bottom surface that lies above and vertically spaced apart from the bottom surface of the semiconductor structure;
- a die, having a side wall surface, a bottom surface, a top surface, the top surface having a plurality of conductive pads that provide external connection points for the die;
- wherein the bottom of the die is adhesively attached to the bottom of the cavity;
- wherein the die is configured to include drive and sense circuits;
- a first non-conductive structure, that touches the die and the semiconductor structure and fills the remainder of the cavity, and includes a plurality of openings to exposes the conductive pads of the die, wherein the first non-conductive structure has top surface that is substantially planar;
- a magnetic core pole structure that touches the first non-conductive structure, wherein the magnetic core pole structure has a longest dimension that lies substantially perpendicular to the substantially planar top surface of the first non-conductive structure;
- a first trace structure that touches the first non-conductive structure, the first trace structure being conductive, having a top surface that lies substantially in a first plane, being spaced apart from the magnetic core pole structure, and having a loop wrapped around the magnetic core pole structure;
- a second non-conductive structure, that touches the first non-conductive structure and the first trace structure, and includes a plurality of openings to exposes the conductive pads of the die, wherein the second non-conductive structure has top surface that is substantially planar;
- a second trace structure that touches the second non-conductive structure, the second trace structure being conductive, having a top surface that lies substantially in a second plane, being spaced apart from the magnetic core pole structure, having a loop wrapped around the magnetic core structure, and being electrically isolated from the first trace structure, the second plane lying above the first plane;
- a third non-conductive structure, that touches the second non-conductive structure and the second trace structure, and includes a plurality of openings to exposes the conductive pads of the die, wherein the third non-conductive structure has top surface that is substantially planar;
- a third trace structure that touches the third non-conductive structure, the third trace structure being conductive, having a top surface that lies substantially in a third plane, being spaced apart from the magnetic core pole structure, and being electrically isolated from the second trace structure;
- a fourth non-conductive structure, that touches the third non-conductive structure and the third trace structure, and includes a plurality of openings to exposes the conductive pads of the die, wherein the fourth non-conductive structure has top surface that is substantially planar;
- and
- a fourth trace structure that touches the fourth non-conductive structure, the fourth trace structure being conductive, having a top surface that lies substantially in a fourth plane, being spaced apart from the magnetic core pole structure, and being electrically isolated from the third trace structure;
- a fifth non-conductive structure, that touches the fourth non-conductive structure and the fourth trace structure, and includes a plurality of openings to exposes the conductive pads of the die, wherein the fifth non-conductive structure has top surface that is substantially planar;
- a plurality bond pad structures that touch the fifth non-conductive structure and extend through the fifth non-conductive structure to electrically couple to the die;
- a non-conductive passivation structure that touches the fifth non-conductive structure and the bond pad structures, wherein the non-conductive passivation structure has a substantially planar surface.
14 more elements
Dependencies are inferred from the claim text.