Ferrite magnetic film structure having magnetic anisotropy, method of manufacturing the same, and planar magnetic device employing ferrite magnetic film structure having magnetic anisotropy

• US 20020048668A1
• Filed: 11/06/2001
• Published: 04/25/2002
• Est. Priority Date: 09/13/1997
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Inoue, Tetsuo
• Granted Patent: US 6,611,035 B2
• Time in Patent Office: Days
• US Class Current: 428/210
• CPC Class Codes: H01F 17/0006 Printed inductances printed coils for dynamo-electric machines H02K3/26; printed circuits H05K
• CPC Class Codes: H01F 41/043 by thick film techniques
• CPC Class Codes: H01F 41/046 structurally combined with ferromagnetic material
• CPC Class Codes: H01L 23/5227 Inductive arrangements or effects of, or between, wiring layers other inductive arrangements H01L23/645
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/09701 Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: Y10T 428/24926 including ceramic, glass, porcelain or quartz layer
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension

Abstract

A ferrite magnetic film structure exhibiting a magnetic anisotropy, the ferrite magnetic film structure comprising, a substrate provided on one main surface thereof with a groove-like recessed portion and with a ridge-like projected portion located neighboring to the groove-like recessed portion, and a ferrite magnetic film constituted by a continuous film having a substantially flat upper surface and formed on one main surface of the substrate, wherein the ferrite magnetic film structure meets the following conditions:

(a/(a+b))(h/(t−h))≧0.047

1≧(a+b)

where “a” is a width of the ridge-like projected portion, b is a width of the groove-like recessed portion, h is a height of step between the groove-like recessed portion and the ridge-like projected portion, t is a thickness of the ferrite magnetic film at the recessed portion, and 1 is a length of the recessed portion and of the projected portion.

Claims

1. A ferrite magnetic film structure exhibiting a magnetic anisotropy, said ferrite magnetic film structure comprising;

a substrate provided on one main surface thereof with a groove-like recessed portion and with a ridge-like projected portion located neighboring to said groove-like recessed portion; and

a ferrite magnetic film constituted by a continuous film having a substantially flat upper surface and formed on one main surface of the substrate;

wherein said ferrite magnetic film structure meets the following conditions;

(a/(a+b))(h/(t−

h))≧

0.047 1≧

(a+b)

where “

a”

is a width of said ridge-like projected portion;

b is a width of said groove-like recessed portion;

h is a height of step between said groove-like recessed portion and said ridge-like projected portion;

t is a thickness of said ferrite magnetic film at the recessed portion; and

1 is a length of said recessed portion and of said projected portion.

2. The ferrite magnetic film structure according to claim 1, wherein said groove-like recessed portion and said ridge-like projected portion are both spiral in shape.

3. The ferrite magnetic film structure according to claim 1, wherein said groove-like recessed portion and said ridge-like projected portion are both concentric in shape.

4. The ferrite magnetic film structure according to claim 1, wherein at least surface portion of said substrate is formed of a metal selected from the group consisting of zirconium, copper and aluminum, and a surface of said substrate to be formed with a magnetic film is covered with a metal diffusion preventive film.

5. The ferrite magnetic film structure according to claim 1, wherein said substrate is formed of an insulating substance selected from the group consisting of SiN and SiO₂.

6. A ferrite magnetic film structure exhibiting a magnetic anisotropy, said ferrite magnetic film structure comprising;

a substrate; and

a ferrite magnetic film formed on one main surface of said substrate and having a spiral pattern or a concentric pattern;

wherein said ferrite magnetic film structure meets the following conditions;

u²/(w²+u²)≧

0.12×

10<sup>−

3</sup>

where w is a width of said ferrite magnetic film; and

u is a thickness of said ferrite magnetic film.

7. The ferrite magnetic film structure according to claim 6, wherein at least surface portion of said substrate is formed of a metal selected from the group consisting of zirconium, copper and aluminum, and a surface of said substrate to be formed with a magnetic film is covered with a metal diffusion preventive film.

8. The ferrite magnetic film structure according to claim 6, wherein said substrate is formed of an insulating substance selected from the group consisting of SiN and SiO₂.

9. A method of manufacturing a ferrite magnetic film structure exhibiting a magnetic anisotropy, said method comprising the steps of;

forming a groove-like recessed portion and a ridge-like projected portion on one main surface of a substrate;

forming a ferrite paste layer by coating a paste containing a ferrite powder on said one main surface; and

baking said ferrite paste to form a ferrite magnetic film constituted by a continuous film having a substantially flat upper surface.

10. The method according to claim 9, wherein said ferrite magnetic film structure meets the following conditions:

(a/(a+b))(h/(t−

h))≧

0.047 1≧

(a+b)

where “

a”

is a width of said ridge-like projected portion;

b is a width of said groove-like recessed portion;

h is a height of step between said groove-like recessed portion and said ridge-like projected portion;

t is a thickness of said ferrite magnetic film at the recessed portion; and

1 is a length of said recessed portion and of said projected portion.

11. The method according to claim 9, wherein said ferrite paste layer is formed by means of a screen printing method.

13. The planar magnetic device according to claim 12, wherein said groove-like recessed portion and said ridge-like projected portion are both spiral in shape.

14. The planar magnetic device according to claim 12, wherein said groove-like recessed portion and said ridge-like projected portion are both concentric in shape.

15. The planar magnetic device according to claim 12, wherein at least surface portion of said substrate is formed of a metal selected from the group consisting of zirconium, copper and aluminum, and a surface of said substrate to be formed with a magnetic film is covered with a metal diffusion preventive film.

16. The planar magnetic device according to claim 12, wherein said substrate is formed of an insulating substance selected from the group consisting of SiN and SiO₂.

18. The planar magnetic device according to claim 17, wherein at least surface portion of said substrate is formed of a metal selected from the group consisting of zirconium, copper and aluminum, and a surface of said substrate to be formed with a magnetic film is covered with a metal diffusion preventive film.

19. The planar magnetic device according to claim 17, wherein said substrate is formed of an insulating substance selected from the group consisting of SiN and SiO₂.

12. A planar magnetic device comprising;

a first ferrite magnetic film structure exhibiting a magnetic anisotropy;

a second ferrite magnetic film structure exhibiting a magnetic anisotropy; and

a planar coil conductor interposed between said first ferrite magnetic film structure and said second ferrite magnetic film structure;

wherein each of said first and second ferrite magnetic film structures comprise;

a substrate provided on one main surface thereof with a groove-like recessed portion and with a ridge-like projected portion located neighboring to said groove-like recessed portion; and

a ferrite magnetic film constituted by a continuous film having a substantially flat upper surface and formed on one main surface of the substrate;

wherein said ferrite magnetic film structure meets the following conditions;

(a/(a+b))(h/(t−

h))≧

0.047 1≧

(a+b)

where “

a”

is a width of said ridge-like projected portion;

b is a width of said groove-like recessed portion;

h is a height of step between said groove-like recessed portion and said ridge-like projected portion;

t is a thickness of said ferrite magnetic film at the recessed portion; and

1 is a length of said recessed portion and of said projected portion.

17. A planar magnetic device comprising;

a first ferrite magnetic film structure exhibiting a magnetic anisotropy;

a second ferrite magnetic film structure exhibiting a magnetic anisotropy; and

a planar coil conductor interposed between said first ferrite magnetic film structure and said second ferrite magnetic film structure;

wherein said first and second ferrite magnetic film structures comprise respectively;

a substrate; and

a ferrite magnetic film formed on one main surface of said substrate and having a spiral pattern or a concentric pattern;

wherein said ferrite magnetic film structure meets the following conditions;

u²/(w²+u²)≧

0.12×

10<sup>−

3</sup>

where w is a width of said ferrite magnetic film; and

u is a thickness of said ferrite magnetic film.

20. A planar magnetic device comprising;

a substrate;

a magnetic film formed on said substrate and exhibiting a magnetic anisotropy; and

a planar coil conductor formed on said magnetic film;

wherein said magnetic film is provided with uniaxial magnetic anisotropy in an in-plane direction of said substrate so as to allow an extending direction of said planar coil conductor to be maintained parallel with easy direction of magnetization, and the entire surface of said magnetic film exhibits hard magnetization against a coil current.