Thin film device

Abstract

A thin film device is provided, in which inductance can be increased when a thin film coil wound on a magnetic film is provided. In a thin film coil wound on a magnetic film, thickness of lower coil portions is smaller than thickness of upper coil portions. Consequently, a magnetic property (permeability) tends to be hardly deteriorated.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plane view showing a planar configuration of a thin film inductor as an application of a thin film device according to a first embodiment of the invention;

FIG. 2 is a section view showing a sectional configuration of the thin film inductor along a line II-II shown in FIG. 1;

FIG. 3 is a section view showing a sectional configuration of the thin film inductor along a line III-III shown in FIG. 1;

FIG. 4 is a section view showing a sectional configuration of the thin film inductor along a line IV-IV shown in FIG. 1;

FIG. 5 is a section view showing a sectional configuration of a thin film inductor as a comparative example to the thin film inductor of an embodiment of the invention;

FIG. 6 is a section view showing a modification on a configuration of the thin film inductor;

FIG. 7 is a section view showing another modification on a configuration of the thin film inductor;

FIG. 8 is a plane view showing a planar configuration of a thin film inductor as an application of a thin film device according to a second embodiment of the invention;

FIG. 9 is a section view showing a sectional configuration of the thin film inductor along a line IX-IX shown in FIG. 8;

FIG. 10 is a section view showing a sectional configuration of the thin film inductor along a line X-X shown in FIG. 8;

FIG. 11 is a section view showing a sectional configuration of the thin film inductor along a line XI-XI shown in FIG. 8;

FIG. 12 is a section view showing a sectional configuration of a thin film inductor of a first comparative example;

FIG. 13 is a section view showing a sectional configuration of a thin film inductor of a second comparative example;

FIG. 14 is a section view showing a modification on a configuration of the thin film inductor of an embodiment of the invention;

FIG. 15 is a section view showing another modification on a configuration of the thin film inductor of an embodiment of the invention;

FIG. 16 is a section view showing still another modification on a configuration of the thin film inductor of an embodiment of the invention;

FIG. 17 is a section view showing still another modification on a configuration of the thin film inductor of an embodiment of the invention;

FIG. 18 is a section view showing still another modification on a configuration of the thin film inductor of an embodiment of the invention;

FIG. 19 is a view showing dependence on a thickness ratio TB/TA of inductance Ldc;

FIG. 20 is a view showing dependence on the thickness ratio TB/TA of inductance L1M;

FIG. 21 is a view showing dependence on the thickness ratio TB/TA of resistance Rdc;

FIG. 22 is a view showing dependence on the thickness ratio TB/TA of resistance R1M;

FIG. 23 is a view showing dependence on the thickness ratio TB/TA of a ratio L1M/Rdc of the inductance L1M to the resistance Rdc; and

FIG. 24 is a view showing dependence on the thickness ratio TB/TA of a ratio Ldc/Rdc of the inductance Ldc to the resistance Rdc.

Claims

1. A thin film device comprising: a substrate,a magnetic film disposed on the substrate, anda thin film coil wound on the magnetic film,wherein the thin film coil includes;a plurality of first coil portions arranged in a layer closer to the substrate,a plurality of second coil portions arranged in a layer away from the substrate, anda plurality of third coil portions connecting the first and second coil portions so that the first, second and third coil portions are combined together in series to form the thin film coil, whereinthickness of the first coil portions is smaller than thickness of the second coil portions.

2. The thin film device according to claim 1 further comprising: two or more additional magnetic films disposed so as to sandwich the magnetic film and the thin film coil.

3. The thin film device according to claim 1: wherein one end or the other end in the longitudinal direction of the second coil portion is located so as to overlap with one end or the other end in the longitudinal direction of the first coil portion, andthe third coil portion is arranged in a position where the second coil portions is overlapped with the first coil portion.

4. A thin film device comprising: a first magnetic film and a second magnetic film disposed oppositely to each other, anda thin film coil wound on the second magnetic film,wherein the thin film coil includes a plurality of first coil portions arranged between the first and the second magnetic films, a plurality of second coil portions arranged at a side opposite to a side of the first coil portions with the second magnetic film in between, and a plurality of third coil portions connecting the first and second coil portions so that the first, second and third coil portions are combined together in series to form the thin film coil, andthickness of the first coil portions in at least ends in a winding direction of the thin film coil is smaller than thickness of the second coil portions.

5. The thin film device according to claim 4: wherein thickness of the respective first coil portions is smaller than the thickness of the second coil portions.

6. The thin film device according to claim 5: wherein the respective first coil portions are equal in thickness to one another.

7. The thin film device according to claim 5: wherein the thickness of the respective first coil portions is large in portions other than the ends compared with the thickness in the ends.

8. The thin film device according to claim 7: wherein the thickness of the respective first coil portions is gradually increased from the ends to the center.

9. The thin film device according to claim 4: wherein one end or the other end in the longitudinal direction of the second coil portion is located so as to overlap with one end or the other end in the longitudinal direction of the first coil portion, andthe third coil portion is arranged in a position where the second coil portion overlaps with the first coil portion.

10. The thin film device according to claim 4: wherein a ratio of a thickness TB of the second coil portions to a-thickness TA of the first coil portions in at least the ends in the winding direction of the thin film coil, namely TB/TA, is in a range of: 1<TB/TA≦2.7.