Integrated circuit inductors

• US 20020095778A1
• Filed: 03/19/2002
• Published: 07/25/2002
• Est. Priority Date: 07/09/1999
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Ahn, Kie Y., Forbes, Leonard
• Granted Patent: US 6,948,230 B2
• Time in Patent Office: Days
• US Class Current: 29/604
• CPC Class Codes: H01F 17/0033 with the coil helically wound around a magnetic core
• CPC Class Codes: H01F 27/2804 Printed windings
• CPC Class Codes: H01F 37/00 Fixed inductances not covered by group H01F17/00
• CPC Class Codes: H01L 27/08 including only semiconductor components of a single kind
• CPC Class Codes: Y10S 257/924 with passive device, e.g. capacitor, or battery, as integral part of housing or housing element, e.g. cap
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor
• CPC Class Codes: Y10T 29/49037 Using reference point/surface to facilitate measuring
• CPC Class Codes: Y10T 29/49069 Data storage inductor or core
• CPC Class Codes: Y10T 29/49071 by winding or coiling
• CPC Class Codes: Y10T 29/49073 by assembling coil and core
• CPC Class Codes: Y10T 29/49075 including permanent magnet or core

Abstract

The invention relates to an inductor comprising a plurality of interconnected conductive segments interwoven with a substrate. The inductance of the inductor is increased through the use of coatings and films of ferromagnetic materials such as magnetic metals, alloys, and oxides. The inductor is compatible with integrated circuit manufacturing techniques and eliminates the need in many systems and circuits for large off chip inductors. A sense and measurement coil, which is fabricated on the same substrate as the inductor, provides the capability to measure the magnetic field or flux produced by the inductor. This on chip measurement capability supplies information that permits circuit engineers to design and fabricate on chip inductors to very tight tolerances.

Claims

1. A method comprising:

boring a plurality for substantially parallel perforations in a substrate having a pair of substantially parallel surfaces;

plugging the plurality of substantially parallel perforations with a highly conductive material to form a highly conductive segment; and

interconnecting the plurality of highly conductive segments to form a conductive path operable for producing a reinforcing magnetic field.

4. The method of claim 1, wherein interconnecting the plurality of highly conductive segments includes joining ends of the highly conductive segments with second highly conductive segments arranged parallel to and adjacent the pair of substantially parallel surfaces.

5. The method of claim 4, wherein the second highly conductive segments comprise a material different than the material forming the highly conductive segments plugging the plurality of substantially parallel perforations.

6. The method of claim 4, wherein boring the plurality of substantially parallel holes includes irradiating at least one of the pair of substantially parallel surfaces with a laser.

7. The method of claim 1, wherein boring the plurality of substantially parallel holes includes drilling into at least one of the substantially parallel surfaces with a drill bit.

8. The method of claim 1, wherein boring the plurality of substantially parallel holes includes etching at least one of the substantially parallel surfaces.

9. The method of claim 1, including coating at least one of the substantially parallel surfaces.

10. The method of claim 9, wherein coating at least one of the substantially parallel surfaces includes forming a magnetic film.

2. A method comprising:

drilling a plurality of substantially parallel holes in a substrate having a plurality of substantially parallel surfaces;

coating at least one of the substantially parallel surfaces with a magnetic material;

filling the plurality of substantially parallel holes with a conductor to form a conductive segment; and

interconnecting the plurality of conductive segments to form a coil operable for producing a magnetic field in the coating.

11. The method of claim 2, further including covering the magnetic film and a portion of the coil traversing the magnetic material with an insulating layer.

12. The method of claim 2, wherein the conductor filling the plurality of substantially parallel holes is copper or aluminum.

13. The method of claim 2, wherein interconnecting the plurality of conductive segments includes providing a second plurality of conductive segments arranged parallel to the substantially parallel surfaces.

14. The method of claim 2, including forming a magnetic layer as part of the coating.

3. A method comprising:

piercing a substrate having a plurality of substantially parallel surfaces to form a plurality of substantially parallel perforations;

coating at least one of the substantially parallel surfaces with an insulating film;

coating the insulating film with a magnetic film;

coating the magnetic film with an insulating material;

depositing in at least two of the plurality of substantially parallel perforations a conductor to form a plurality of conductive segments; and

coupling the plurality of conductive segments with a conductive material to form a loop.

15. The method of claim 3, wherein piercing the substrate includes irradiating one of the parallel surfaces with a laser.

16. The method of claim 3, wherein piercing the substrate includes drilling through one of the parallel surfaces with a drill bit.

17. The method of claim 3, wherein piercing the substrate includes etching one of the surfaces.

18. The method of claim 3, wherein the conductive segments comprise the same material as the conductive material.

19. The method of claim 3, wherein coating with the insulating film includes depositing a layer of inorganic oxide.

20. A method of forming an inductor, comprising:

forming a plurality of holes connecting first and second opposing surfaces of a substrate;

forming a magnetic film over a portion of the first surface;

filling the plurality of holes with a first conductive material to form first conductive segments; and

connecting the first conductive segments with second conductive segments to form a coil, with a portion of the first conductive segments traversing the magnetic film.

21. The method of claim 20, wherein forming the plurality of holes includes irradiating one of the first and second surfaces with a laser.

22. The method of claim 20, wherein forming the plurality of holes includes drilling through one of the first and second surfaces with a drill bit.

23. The method of claim 20, wherein forming the plurality of holes includes etching one of the first and second surfaces.

24. The method of claim 20, including forming an insulating layer over the magnetic film.

25. The method of claim 20, including forming the insulating layer to cover the second conductive segments.

27. The method of claim 26, wherein forming the plurality of through holes includes irradiating the substrate with a laser.

28. The method of claim 26, wherein forming the plurality of through holes includes drilling through the substrate with a drill bit.

29. The method of claim 26, wherein forming the plurality of through holes includes etching the substrate.

30. The method of claim 26, comprising forming the plurality of through holes such that the coil has a triangular cross-section.

31. The method of claim 26, comprising forming the plurality of through holes such that the coil has a rectangular cross-section.

26. A method of forming an inductor, comprising:

forming a plurality of through holes in a first region of a substrate;

coating a surface portion of the first region of the substrate with a magnetic film;

depositing a first conductor in the plurality of through holes; and

connecting the conductor formed in the plurality of through holes with a second conductor so as to form a coil surrounding the first region of the substrate.

32. A method of forming an inductor, comprising:

forming first and second sets of substantially parallel holes between opposing surfaces of a semiconductor substrate;

filling the first and second sets of substantially parallel holes with a conductive material to form first coil segments; and

connecting the first coil segments with second coil segments that traverse respective portion of the opposing surfaces of the semiconductor substrate.

33. The method of claim 32, wherein forming the first and second sets of substantially parallel holes includes irradiating at least one of the opposing surfaces with a laser.

34. The method of claim 32, wherein forming the first and second sets of substantially parallel holes includes drilling through at least one of the opposing surfaces with a drill bit.

35. The method of claim 32, wherein forming the first and second sets of substantially parallel holes includes etching at least one of the opposing surfaces.

37. The method of claim 36, further including forming a magnetic film on a surface of the substrate and traversing the magnetic film with a portion of the second conductor.

38. The method of claim 36, wherein boring the plurality of holes includes irradiating a substrate surface with a laser.

39. The method of claim 36, wherein boring the plurality of holes includes drilling through a substrate surface with a drill bit.

40. The method of claim 36, wherein boring the plurality of holes includes etching a substrate surface.

36. A method of forming an inductor, comprising:

boring a plurality of holes in a substrate;

filling the plurality of holes with a first conductor;

connecting the first conductor with a second conductor to form a coil that surrounds a portion of the substrate.