Method for fabricating inductors with deposition-induced magnetically-anisotropic cores

Patent metadata

Field	Value
Publication number	US-11302469-B2
Application number	US-201916257392-A
Country	US
Kind code	B2
Filing date	Jan 25, 2019
Priority date	Jun 23, 2014
Publication date	Apr 12, 2022
Grant date	Apr 12, 2022

Abstract

A method of fabricating an inductor includes (a) forming a ferromagnetic core on a semiconductor substrate, the ferromagnetic core lying in a core plane and (b) fabricating an inductor coil that winds around the ferromagnetic core, the inductor coil configured to generate an inductor magnetic field that passes through the ferromagnetic core in a first direction parallel to the core plane. While forming the ferromagnetic core, the method further includes (1) generating a bias magnetic field that passes through the ferromagnetic core in a second direction that is orthogonal to the first direction, and (2) inducing a magnetic anisotropy in the ferromagnetic core with the bias magnetic field.

First claim

What is claimed is:

1. A method of fabricating an inductor, the method comprising:
depositing a ferromagnetic material on a substrate;
defining a pattern in the ferromagnetic material to form a ferromagnetic core on the substrate, the ferromagnetic core lying in a core plane;
fabricating an inductor coil that winds around the ferromagnetic core, the inductor coil configured to generate an inductor magnetic field that passes through the ferromagnetic core in a first direction parallel to the core plane; and
while depositing the ferromagnetic material:
generating a bias magnetic field that passes through the ferromagnetic material in a second direction that is orthogonal to the first direction; and
inducing a magnetic anisotropy in the ferromagnetic material with the bias magnetic field,
wherein inducing the magnetic anisotropy further comprises:
with the bias magnetic field, inducing an easy axis of magnetization in the ferromagnetic material, the easy axis parallel to the second direction, and
inducing a hard axis of magnetization in the ferromagnetic material, the hard axis orthogonal to the easy axis.

2. The method of claim 1 , wherein the hard axis is parallel to the first direction.

3. The method of claim 1 , further comprising, while depositing the ferromagnetic material, applying current in a bias coil disposed on the substrate to generate the bias magnetic field.

4. The method of claim 3 , further comprising applying at least 10 mA of current in the bias coil.

5. The method of claim 3 , further comprising fabricating the bias coil on the substrate, the bias coil disposed parallel to the core plane.

6. The method of claim 5 , further comprising disposing the bias coil between the ferromagnetic core and the substrate.

7. The method of claim 6 , further comprising disposing the bias coil between the inductor coil and the substrate.

8. The method of claim 6 , wherein the inductor coil includes a top conductor, a bottom conductor, and a VIA that is electrically coupled to the top and bottom conductors, and the method further comprises disposing the bias coil between the ferromagnetic core and the bottom conductor.

9. The method of claim 5 , further comprising aligning an axis of symmetry of the bias coil with a target axis of symmetry of the ferromagnetic core.

10. The method of claim 1 , wherein the ferromagnetic core is formed on a first substrate and the method further comprises:
providing relative movement between the first substrate and a second substrate having a bias coil disposed thereon such that the bias coil on the second substrate and a target location for the ferromagnetic core on the first substrate are within a predetermined distance of one another; and
generating the bias magnetic field with the bias coil.

11. The method of claim 10 , further comprising applying current in the bias coil to generate the bias magnetic field.

12. The method of claim 11 , further comprising applying at least 10 mA of current in the bias coil.

13. The method of claim 10 , wherein the relative movement between the first substrate and the second substrate results in a relative positioning thereof in which the first substrate and the second substrate are in contact with one another.

14. The method of claim 10 , wherein the relative movement between the first substrate and the second substrate aligns the bias coil and a target location for the ferromagnetic core.

15. The method of claim 1 , wherein the ferromagnetic material is deposited on a semiconductor substrate.

16. The method of claim 1 , wherein the ferromagnetic core is formed on a semiconductor substrate.

17. A method of fabricating an inductor, the method comprising:
depositing a ferromagnetic material on a substrate;
defining a pattern in the ferromagnetic material to form a ferromagnetic core on the substrate, the ferromagnetic core lying in a core plane;
fabricating an inductor coil that winds around the ferromagnetic core, the inductor coil configured to generate an inductor magnetic field that passes through the ferromagnetic core in a first direction parallel to the core plane; and
while depositing the ferromagnetic material:
generating a bias magnetic field that passes through the ferromagnetic material in a second direction that is orthogonal to the first direction;
inducing a magnetic anisotropy in the ferromagnetic material with the bias magnetic field; and
while depositing the ferromagnetic material, applying current in a bias coil disposed on the substrate to generate the bias magnetic field.

18. The method of claim 17 , wherein inducing the magnetic anisotropy further comprises inducing a hard axis of magnetization in the ferromagnetic material, the hard axis orthogonal to the easy axis.

19. The method of claim 18 wherein the hard axis is parallel to the first direction.

20. The method of claim 17 , further comprising applying at least 10 mA of current in the bias coil.

21. The method of claim 17 , further comprising fabricating the bias coil on the substrate, the bias coil disposed parallel to the core plane.

22. The method of claim 21 , further comprising disposing the bias coil between the ferromagnetic core and the substrate.

23. The method of claim 22 , further comprising disposing the bias coil between the inductor coil and the substrate.

24. The method of claim 22 , wherein the inductor coil includes a top conductor, a bottom conductor, and a VIA that is electrically coupled to the top and bottom conductors, and the method further comprises disposing the bias coil between the ferromagnetic core and the bottom conductor.

25. The method of claim 21 , further comprising aligning an axis of symmetry of the bias coil with a target axis of symmetry of the ferromagnetic core.

26. The method of claim 17 , wherein the ferromagnetic material is deposited on a semiconductor substrate.

27. The method of claim 17 , wherein the ferromagnetic core is formed on a semiconductor substrate.

28. A method of fabricating an inductor, the method comprising:
depositing a ferromagnetic material on a substrate;
defining a pattern in the ferromagnetic material to form a ferromagnetic core on the substrate, the ferromagnetic core lying in a core plane;
fabricating an inductor coil that winds around the ferromagnetic core, the inductor coil configured to generate an inductor magnetic field that passes through the ferromagnetic core in a first direction parallel to the core plane; and
while depositing the ferromagnetic material:
generating a bias magnetic field that passes through the ferromagnetic material in a second direction that is orthogonal to the first direction; and
inducing a magnetic anisotropy in the ferromagnetic material with the bias magnetic field,

wherein the ferromagnetic core is formed on a first substrate and the method further comprises:
providing relative movement between the first substrate and a second substrate having a bias coil disposed thereon such that the bias coil on the second substrate and a target location for the ferromagnetic core on the first substrate are within a predetermined distance of one another; and
generating the bias magnetic field with the bias coil.

29. The method of claim 28 , wherein inducing the magnetic anisotropy further comprises inducing a hard axis of magnetization in the ferromagnetic material, the

Assignees

• Ferric Inc

Inventors

• Sturcken Noah
• Davies Ryan
• Lekas Michael

Classifications

• H10D1/20 Primary

  Inductors · CPC title

• H01F41/26

  using electric currents {, e.g. electroplating} · CPC title

• Y10T29/49073

  by assembling coil and core · CPC title

• Y10T29/4902

  Electromagnet, transformer or inductor · CPC title

• H01F17/0006

  Printed inductances (printed coils for dynamo-electric machines H02K3/26; printed circuits H05K) · CPC title