Thin film device

Abstract

A thin film device, which can maintain desirable performance characteristics by reducing parasitic capacitance and increasing the Q factor even when a thin film coil of a solenoid type is equipped, is provided. The thin film coil of a solenoid type has a cross sectional width which varies with position along a film thickness direction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view showing a top view configuration of a thin film inductor as one application of a thin film device according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a cross-sectional configuration of the thin film inductor taken along line II-II of FIG. 1.

FIG. 3 is a sectional view showing a cross-sectional configuration of the thin film inductor taken along line III-III of FIG. 1.

FIG. 4 is a sectional view showing a cross-sectional configuration of the thin film inductor taken along line IV-IV of FIG. 1.

FIG. 5 is an enlarged sectional view showing an enlarged cross-sectional configuration of a part of the thin film coil illustrated in FIG. 2.

FIG. 6 is a sectional view showing a cross-sectional configuration of a thin film inductor as a comparative example to the thin film inductor of the present invention.

FIG. 7 is an enlarged sectional view showing an enlarged cross-sectional configuration of a part of the thin film coil illustrated in FIG. 6.

FIG. 8 is a sectional view showing a first modification with regard to a construction of the thin film inductor.

FIG. 9 is a sectional view showing a second modification with regard to a construction of the thin film inductor.

FIG. 10 is a sectional view showing a third modification with regard to a construction of the thin film inductor.

FIG. 11 is a sectional view showing a fourth modification with regard to a construction of the thin film inductor.

FIG. 12 is a sectional view showing a fifth modification with regard to a construction of the thin film inductor.

FIG. 13 is a sectional view showing a sixth modification with regard to a construction of the thin film inductor.

FIG. 14 is a sectional view showing a seventh modification with regard to a construction of the thin film inductor.

FIG. 15 is a sectional view showing an eighth modification with regard to a construction of the thin film inductor.

FIG. 16 is a sectional view showing a ninth modification with regard to a construction of the thin film inductor.

FIG. 17 is a sectional view showing a cross-sectional configuration of a thin film inductor as one application of a thin film device according to a second embodiment of the present invention.

FIG. 18 is an enlarged sectional view showing an enlarged cross-sectional configuration of a part of the thin film coil illustrated in FIG. 17.

FIG. 19 is a sectional view for explaining a step of fabrication process of a thin film coil.

FIG. 20 is a sectional view for explaining a step subsequent to that of FIG. 19.

FIG. 21 is a sectional view for explaining a step subsequent to that of FIG. 20.

FIG. 22 is a sectional view for explaining a step subsequent to that of FIG. 21.

FIG. 23 is a sectional view showing a first modification with regard to a construction of the thin film inductor according to the second embodiment of the present invention.

FIG. 24 is a sectional view showing a second modification with regard to a construction of the thin film inductor according to the second embodiment of the present invention.

Claims

1. A thin film device comprising a thin film coil of a solenoid type, the thin film coil having a cross sectional width which varies with position along a film thickness direction.

2. The thin film device according to claim 1, wherein the cross sectional width is narrowed at one end or both ends, in the film thickness direction, of a cross section of the thin film coil.

3. The thin film device according to claim 1, further comprising a substrate supporting the thin film coil, the thin film coil including; 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, whereinthe cross sectional width of at least one of the first and second coil portion is narrowed at one end, facing the other coil portion, in the film thickness direction.

4. The thin film device according to claim 3, 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 portions is arranged in a position where the second coil portion overlaps with the first coil portion.

5. The thin film device according to claim 1, further comprising: a substrate supporting the thin film coil; andat least one of a first, a second and a third magnetic film, the first magnetic film being wound with the thin film coil, the second magnetic film being arranged on a substrate-side of the thin film coil, and the third magnetic film being arranged on an opposite-side of the thin film coil from the substrate, whereinthe cross sectional width is narrowed at one end, facing the first, second or third magnetic film, in the film thickness direction.

6. The thin film device according to claim 1, further comprising a substrate supporting the thin film coil, the thin film coil including; 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, whereinthe cross sectional width of at least one of the first and second coil portion is narrower at a part closer to the substrate rather than at a part away from the substrate.

7. The thin film device according to claim 6, wherein the cross sectional width of the first coil portion is uniform along a film thickness direction, and the cross sectional width of the second coil portion at a part closer to the substrate is narrower than that at a part away from the substrate, and is narrower than the cross sectional width of the first coil portion.

8. The thin film device according to claim 6, wherein the cross section of at least one of the first and second coil portion is mushroom-shaped.

9. The thin film device according to any of claim 6, further comprising at least one of a first and a second magnetic films, the first magnetic film being wound with the thin film coil, and the second magnetic film being arranged on a substrate-side of the thin film coil.

10. A thin film device, comprising a thin film coil of a solenoid type, a space between coil turns of the thin film coil varying with position along a film thickness direction.

11. The thin film device according to claim 10, wherein the space is widened at one end or both ends, in the film thickness direction, of the coil turn.

12. A thin film device, comprising a thin film coil of a solenoid type, a cross section of the thin film coil having a shape in which a side-edge of a cross section of a turn is non-parallel to a side-end of a cross section of an adjacent turn.