THIN FILM INDUCTOR WITH EXTENDED YOKES

• US 20150279546A1
• Filed: 03/31/2014
• Published: 10/01/2015
• Est. Priority Date: 03/31/2014
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Fontana, Robert E. Jr., Herget, Philipp
• Granted Patent: US 9,324,489 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01F 17/0006 Printed inductances printed coils for dynamo-electric machines H02K3/26; printed circuits H05K
• CPC Class Codes: H01F 2017/0053 with means to reduce eddy currents
• CPC Class Codes: H01F 2017/0066 with a magnetic layer
• CPC Class Codes: H01F 2027/2809 on stacked layers
• CPC Class Codes: H01F 27/2804 Printed windings
• CPC Class Codes: H01F 41/042 by thin film techniques

Abstract

A thin film inductor with top and bottom pole pieces that are mechanically connected to each other at at least two via zones, to create a magnetically permeable yoke that defines at least one interior space. Enclosed portion(s) of a winding member pass through the interior space(s) of the yoke. The enclosed portion(s) of the winding member define an axial direction and a transverse direction. The pole pieces extend beyond the via zones in the axial and/or transverse direction. The extended pole pieces improve magnetic performance of the thin film inductor, by effectively moving pole piece edges away from locations of high magnetic flux density.

Claims

1. A thin film inductor where a stacking direction of the layers of the thin film structure defines a vertical direction, the inductor comprising:

a rectangular bottom yoke portion;

a rectangular top yoke portion;

a magnetic via zone set including at least a first magnetic via zone and a second magnetic via zone, with each magnetic via zone of the magnetic via zone set being structured, sized, shaped, connected and/or located to form a low magnetic reluctance path between the top yoke portion and the bottom yoke portion; and

a first current carrier portion;

wherein;

the first magnetic via zone and the second magnetic via zone are elongated in an axial direction;

the first magnetic via zone and the second magnetic via zone are spaced apart in a transverse direction by a distance W;

at least a portion of the first current carrier portion is located to pass between;

(i) the top yoke portion and the bottom yoke portion, and (ii) the first via zone and the second via zone;

the first and second yoke portions, the first current carrier portion and the first set of via zones are located, sized, shaped and/or connected to act as an inductor when current passes through the first current carrier portion;

each of the top and bottom yoke portions have;

(i) a first axial end terminating in a first transverse edge, and (ii) a second axial end terminating in a second transverse edge; and

at least one of the first transverse edge of the top yoke, the second transverse edge of the top yoke, the first transverse edge of the bottom yoke, the second transverse edge of the bottom yoke is spaced apart from the first and second via zones in the axial direction by at least 0.5 times W.

2. The inductor of claim 1 wherein:

the first transverse edge of the top yoke and the second transverse edge of the top yoke are both spaced apart from the first and second via zones in the axial direction by at least 0.5 times W.

3. The inductor of claim 1 wherein:

the first transverse edge of the top yoke and the second transverse edge of the top yoke, the first transverse edge of the bottom yoke are all spaced apart from the first and second via zones in the axial direction by at least 0.5 times W; and

the second transverse edge of the bottom yoke is spaced apart from the first and second via zones in the axial direction by less than 0.5 times W.

4. The inductor of claim 1 wherein:

at least one of the first transverse edge of the top yoke, the second transverse edge of the top yoke, the first transverse edge of the bottom yoke, the second transverse edge of the bottom yoke is spaced apart from the first and second via zones in the axial direction by at least 1.0 times W.

5. The inductor of claim 1 wherein:

the first and second via zones are each defined by locations where the top and bottom yoke are in contact with each other.

6. The inductor of claim 1 wherein:

the first and second via zones each include magnetically permeable material extending vertically from the top yoke portion down to the bottom yoke portion.

7. The inductor of claim 1 wherein:

the magnetic via zone set further includes a third via zone; and

the first current carrier portion includes a first portion located between the first and second magnetic via zones and a second portion located between the first and third magnetic via zones.

8. A thin film inductor where a stacking direction of the layers of the thin film structure defines a vertical direction, the inductor comprising:

a rectangular bottom yoke portion;

a rectangular top yoke portion;

a magnetic via zone set including at least a first magnetic via zone and a second magnetic via zone, and with each magnetic via zone of the magnetic via zone set being structured, sized, shaped, connected and/or located to form a low magnetic reluctance path between the top yoke portion and the bottom yoke portion; and

a first current carrier portion;

wherein;

the via zones of the magnetic via zone set are elongated in an axial direction and at least substantially aligned with each other in the axial direction;

the via zones of the magnetic via zone set are spaced apart from each other in a transverse direction by a distance W;

the via zones of the magnetic via zone set each have a transverse direction width L;

the first and second yoke portions, the first current carrier portion and the first set of via zones are located, sized, shaped and/or connected to act as an inductor when current passes through the first current carrier portion;

each of the top and bottom yoke portions have;

(i) a first transverse end terminating in a first axial edge, and (ii) a second transverse end terminating in a second axial edge; and

at least one of the first axial edge of the top yoke, the second axial edge of the top yoke, the first axial edge of the bottom yoke, the second axial edge of the bottom yoke is spaced apart from a closest via zone of the via zone of the magnetic via zone set in the transverse direction by at least L.

9. The inductor of claim 8 wherein:

the first axial edge of the top yoke and the second axial edge of the top yoke are each spaced apart from a closer via zone of the magnetic via zone set in the transverse direction by at least L.

10. The inductor of claim 8 wherein:

the via zones of the magnetic via zone set are each defined by locations where the top and bottom yoke are in contact with each other.

11. The inductor of claim 8 wherein:

the via zones of the magnetic via zone set each include magnetically permeable material extending vertically from the top yoke portion down to the bottom yoke portion.

12. The inductor of claim 8 wherein:

the magnetic via zone set includes at least a first, a second and a third magnetic via zone; and

the first current carrier portion includes a first portion located between a first magnetic via zone of the set of magnetic via zones and a second magnetic via zone of the set of magnetic via zones and a second portion located between the first magnetic via zone and third via zones.

13. A thin film inductor where a stacking direction of the layers of the thin film defines a vertical direction, the inductor comprising:

a rectangular bottom yoke portion;

a rectangular top yoke portion;

a magnetic via zone set including a plurality of magnetic via zones, with each magnetic via zone of the magnetic via zone set being structured, sized, shaped, connected and/or located to form a low magnetic reluctance path between the top yoke portion and the bottom yoke portion;

a first current carrier portion; and

a first electrical via;

wherein;

the via zones of the magnetic via zone set are elongated in an axial direction and at least substantially aligned with each other in the axial direction;

the via zones of the magnetic via zone set are spaced apart from each other in a transverse direction;

the first and second yoke portions, the first current carrier portion and the first set of via zones are located, sized, shaped and/or connected to act as an inductor when current passes through the first current carrier portion;

the top yoke portion includes a first axial end terminating in a first transverse edge;

the bottom yoke portion includes a first axial end terminating in a first transverse edge;

the first transverse edges of the top and bottom yoke portions are offset from each other to define a gap footprint;

the first electrical via extends in the vertical direction;

the first electrical via is electrically connected to the first current carrying portion; and

a footprint of the first electrical via is located at least substantially within the gap footprint.

14. The inductor of claim 13 wherein:

the via zones of the magnetic via zone set are each defined by locations where the top and bottom yoke are in contact with each other.

15. The inductor of claim 13 wherein:

the via zones of the magnetic via zone set each include magnetically permeable material extending vertically from the top yoke portion down to the bottom yoke portion.

16. The inductor of claim 13 wherein:

the magnetic via zone set includes at least three via zones; and

the first current carrier portion includes a first portion located between the first and second magnetic via zones and a second portion located between the first and third magnetic via zones.

17. The inductor of claim 13 wherein:

the first transverse edge of the top yoke portion is spaced apart in the axial direction from the magnetic via set by distance L1;

the first transverse edge of bottom yoke portion is spaced apart in the axial direction from the magnetic via set by distance L2;

L1 is greater than L2 by at least the diameter of the first electric via; and

the first electric via extends downwards from the first current carrier portion.