© TOKIN 20191/23

Soft magnetic Metal-flake Composite Material

Suitable for High Frequency Power Modules

19 Mar. 2019

Ken’ichi Chata’ni

TOKIN Corporation

© TOKIN 20192/23

Ken’ichi Chata’ni, Ph.D.(Physics)

Manager, Advanced Materials R&D DivisionTOKIN Corporation

7-1 Koriyama 6-Chome, Taihaku-ku, Sendai, Miyagi 982-8510 Japan

kenichichatani@kemet.com

© TOKIN 20193/23

TOKIN History

1930 19801930

Name changed to TOKIN Corporationbecome a 100% subsidiary of the United States based KEMET Corporation

1990 2000 2010

April 1938 as University Startups

Established to commercialize KS magnetic steel (by Prof.

Kotaro Honda) and Sendust (by Prof. Masumoto Hakaru), both

invented at Tohoku Imperial University, Sendai, Japan.

October 1988

April 2002

February 2013

Became NEC TOKIN Corporation(3 SBUs from NEC: capacitors, relays, and batteries)

Name changed to

TOKIN Corporation

Started business and capital partnership

with KEMET Corporation

April 2017

Main ProductsTantalum capacitors,

Electric double-layer capacitors,

EMI/Noise suppression components,

Power inductors, Transformers,

Piezoelectric devices, Sensors.S

© TOKIN 20194/23

Material characteristics of FlakeCompositeTM ,

in comparison with existing magnetic materials.

-Permeability, magnetic saturation, core loss, etc.

Inductor performance benchmarking.

PCB embedded inductor test fabrication result.

© TOKIN 20195/23

Demands: Shorten the distance from DC/DC converter to load.

Higher DC current / Higher switching frequency

Motivation

Back surface mount

Processer

Inductor Inductor

Inductor

Processer

PCB embedding

Processer

3D mount

Processer

Conventional

Spread of GaN

Integratable L, C

Low-profiled inductor for integrated DC/DC converter is required.

PCB embed enabling magnetic material will also be required in future.

Inductor

© TOKIN 20196/23

FlakeCompositeConventional Metal composite

Permeability >300(Same as ferrites)

< 40

Metal-flake

Compacting

Technology

Thickness >0.5mmBrittle

>50μmFlexible

Heat durability <200℃Organic binder

>200℃Inorganic binder

Enable PCB Embedding

Favorable for power modules

Smaller component's volume

What is FlakeCompositeTM?

t=50μm

© TOKIN 20197/23

0.0

0.5

1.0

1.5

2.0

100 100010

Bs(T

)

MnZnNiZn

CoZrO(film)

CoZrTa(film)

CoＮｉFe(film)

Fe nanocrystal

Permalloy

FeSiAl(Sendust)

FeSi

Fe amorphous

Permeability (1MHz)

PCB embeddedMagnetic Material

Conventional metal composite Low permeability

Ferrites

Deposited Film

Brittle

Difficult to increase

the core volume.

High permeability (300 at 1 MHz.)

50m to 2mm thickness

Thin, Flexible(Rigid)

FlakeComposite

Comparison of Magnetic Materials for PCB Embedding

© TOKIN 20198/23

Powder Shape Permeability Min. bend radius(Arb. unit)

35 10

160 4

300 1

30m

Effect of Powder Shape on Permeability and Flexibility

10 times improvement in

permeability and flexibility

t=50μm

© TOKIN 20199/23

0

100

200

300

400

0.1 1 10 100

Perm

eab

ility

(Re, I

m)

Frequency(MHz)

NiZn ferrite

FlakeComposite

μ’// = 300

μ≦ 5

Comparable to NiZn ferrite for MHz

power application.

Frequency dispersion of complex permeability

Limitation

Lower Out-plane permeability.

Perm

eabili

ty (

Re,

Im)

Frequency (MHz)

Permeability vs Frequency

© TOKIN 201910/23

0

500

1000

1500

-50 -25 0 25 50 75 100 125 150 175

Pcv(m

W/cc, 1M

Hz

Bm

25m

T)

Temp (℃)

0

1000

2000

0 1 2 3 4 5

Pcv(m

W/cc)

f(MHz)

f×Bm=25MHz・mT

23℃

Core loss of FlakeComposite is comparable to NiZn ferrite,

but much larger than MnZn ferrite at few MHz.

NiZn ferrite

MnZn ferrite

Conventional

Metal Composite

Core Loss vs Temp.

FlakeComposite

FlakeComposite

Core Loss

© TOKIN 201911/23

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 2000 4000 6000 8000

B (

T)

H (A/m)

Soft-saturation in FlakeComposite.

Smaller drop of saturated magnetic moment against temperature,

comparing to MnZn ferrite.

125℃

25℃

MnZn ferrite

FlakeComposite

Conventional

Metal Composite

Magnetic Saturation (BH curve)

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0

10

20

30

40

50

60

70

80

0 2000 4000 6000 8000

Perm

eab

ility

Hdc(A/m)

125℃

25℃

MnZn ferrite

FlakeComposite

Conventional

Metal Composite

In metals, permeability under DC-bias field is insensitive to temperature.

In metals, permeability survives under high DC-bias field.

In MnZn ferrite and FlakeComposite, effective

permeability under zero bias field is tuned to be 70 by

corresponding demagnetizing coefficient, i.e, air-gap.

N=0.01384

N=0.01091

N=0

Permeability under DC-bias Field

© TOKIN 201913/23

0

50

100

150

200

250

300

0.1 1 10 100

Pe

rme

ab

ilit

y(R

e,

Im)

Frequency(MHz)

0

10

20

30

40

50

60

70

80

90

100

0 500 1000

Perm

eab

ilit

y C

han

ge(%

)

Plane Pressure(kgf/cm2)

Only 7.6％ permeability decrease

under 1000kgf/cm2 compression.

Plane Pressure(kgf/cm2)

-7.6%

FlakeComposite

Apply 1000kgf/cm2 plane pressure

on the toroidal core.

After 1000kgf/cm2

compression

Initial

Only 2.7% permeability decrease

after 1000kgf/cm2 compression.

No apparent damage was found.

Effect of Plane Compression

© TOKIN 201914/23

Material characteristics of FlakeCompositeTM ,

in comparison with existing magnetic materials.

-Permeability, magnetic saturation, core loss, etc.

Inductor performance benchmarking.

PCB embedded inductor test fabrication result.

© TOKIN 201915/23

Lateral flux

h

Vertical flux

1turn

2turn3turn

Lateral Flux Inductor Structure

Qiang Li, Fred C. Lee, “High Inductance Density Low-Profile Inductor Structure for Integrated Point-of-Load Converter”, 2009

IEEE Applied Power Electronics Conference and Exposition (APEC), Washington, District of Columbia, Feb. 15 – 19, 2009, pp.

1011 – 1017.

Dongbin Hou, Yipeng Su, Qiang Li, Fred C. Lee, “Improving the Efficiency and Dynamics of 3D Integrated

POL”, IEEE Applied Power Electronics Conference and Exposition (APEC), 2015, pp. 1011 – 1017.

FlakeComposite is suitable to

demonstrate the proposed

advantage of “Lateral flux”

inductor design.

As inductor goes thinner, the

advantage of “Lateral flux”

inductor structure should be

more prominent.

© TOKIN 201916/23

0

10000

20000

30000

0 1 2 3 4 5 6

L x

Im

ax /

DC

R(n

H･A

/mΩ

)

Inductor Height(mm)Imax≧20A

FlakeComposite

Lateral flux

The advantage of FlakeComposite Lateral flux inductor becomes

prominent as the inductor height goes lower.

Benchmarking Result

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Storage Result (N=22)

-50℃ 1000h Pass

150℃ 1000h Pass

Unbiased Hast

With MSL 3

Pre-Conditioning130℃85% 96h

Pass33.3psia(2.3atm)

JESD22-A119 JESD22-A103 Condition B

Heat Cycle

-65⇔150℃ 500cycle Pass

JESD22-A104 Condition C Soak Mode 4

JESD22-A118

MSL test (Level 1)

Pre-bake 125℃ 24h

PassMoisture Soak 85℃85%RH 192h

Reflow 260℃ x 3

J-STD-020E

Sample Structure

・Tin plated lead frame and Cu pins

(without insulation coating) are attached

on the FlakeComposite core. Image

Hi Temp and Humidity

85℃85% 1000h Pass

MIL-STD-202 Method 103

• Acceptance Criteria:

・ Change of Ls, Rs and

DCR<10% pre-test to post-test.

・ No cracks, chips or

discoloration

AEC-Q200 compatible. (RoHS2.0, Halogen free, REACH compliant.)

13mm

Reliability Test Example (On samples to CPES)

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Material characteristics of FlakeCompositeTM ,

in comparison with existing magnetic materials.

-Permeability, magnetic saturation, core loss, etc.

Inductor performance benchmarking.

PCB embedded inductor test fabrication result.

© TOKIN 201919/23

Y. Su, W. Zhang, Q. Li, F. C. Lee, and M. Mu, "High frequency integrated Point of Load

(POL) module with PCB embedded inductor substrate," in Energy Conversion Congress

and Exposition (ECCE), 2013 IEEE, 2013, pp. 1243-1250.

Similar prototypes were fabricated.

PCB Embedded Inductor Demonstrated by CPES

© TOKIN 201920/23

2 turn

DCR

2.8mΩ

3 turn

DCR

4.4mΩ

With inserted

pins

0.8mΩ

With inserted

pins

2.1mΩ

0

50

100

150

200

250

300

350

0 10 20 30 40

L(n

H)

@1M

Hz

Idc(A)

2 turn

3 turn

Upside Downside

Upside Downside

t2.5mm

12mm

Embedded core size

9 x 8 x t1.5mm

PCB Embedded Inductor Prototype

Cu t=0.2

CuΦ

=0.8

Flake

CompositeFlake

Composite

t=2.7mmFR4

© TOKIN 201921/23

0

10

20

30

235 255 275 295 315

Co

unt

L(nH, 1MHz)

0

10

20

30

105 115 125 135 145

Co

unt

L(nH, 1MHz)

0

25

50

75

100

125

150

1 10 100 1000

L(n

H)

Frequency(MHz)

1

10

100

1000

1 10 100 1000

|Z|(Ω

)

Frequency(MHz)

0

100

200

300

1 10 100 1000

L(n

H)

Frequency(MHz)

1

10

100

1000

1 10 100 1000

|Z|(Ω

)

Frequency(MHz)

2 turn (n=100)

3 turn (n=100)

－10%

±3σ

±3σ

+10%Ave.

125nH

Ave.

277nH－10% +10%

SRF=400MHz

SRF=250MHz

Tight tolerance of inductance is readily achieved in prototypes.

Dispersion of Inductance , |Z|

© TOKIN 201922/23

PCB embedded inductor to minimize:

- PCB board area.

- parasitic inductance of Cu trace.

Power Inductors

Ferrite FlakeCompositeTM

40% height reduction with

FlakeComposite inductor.

Embedded noise shielding layer

Flexible shielding layer (for WPT)

- Combined with PCB embedding technology.

FlexSuppressor® Flex "Embedded"

Suppressor

Magnetic Sheets

Application Target

© TOKIN 201923/23

FlakeCompositeTM is:

-Thin, Flexible, PCB-embed-enabling,

-High permeability at multi-MHz swithcing frequency,

-High-saturated magnetic moment than ferrite,

-High temperature tolerant

soft magnetic material for power supply application.

We believe this material will contribute to the miniturization of

electronic circuits, especially in:

- DC/DC converters,

- Wireless Power Transfer system.

We are continuing to scale-up this technology for use in several applications.

Summary

Thank you very much for your attention.